Methods, apparatuses and systems directed to phase-continuous frequency selective precoding

ABSTRACT

Methods, apparatuses, systems, devices, and computer program products directed to phase-continuous frequency selective precoding are provided. Included among these classes are methods for use in connection with dynamic precoding resource block group (PRG) configuration and with codebook based transmission configuration. A representative of such methods may include any of receiving signaling indicating transmit precoding information; determining a candidate PRG size using any of the transmit precoding information, a rule for determining a PRG size and configured PRG sizes; and configuring or reconfiguring a wireless transmit/receive device in accordance with the candidate PRG size. Another of the representative methods may include reporting a transmission coherence capability of a wireless transmit/receive unit; receiving a codebook subset restriction (CBSR) commensurate with the transmission coherence capability; determining a transmit precoding matrix indices (TPMI) size based on the CB SR; receiving a TPMI; and detecting or decoding the TPMI based on the determined TPMI size.

BACKGROUND Field

This application is related to wireless communications.

Related Art

In Long Term Evolution (LTE), a precoding resource block group (PRG) maybe utilized to configure precoding granularity in a frequency domain andto facilitate channel estimation at a wireless transmit/receive unit(WTRU), whereby the WTRU carries out channel estimation across a groupof consecutive physical resource blocks (PRBs). In LTE, the PRG is afunction of the system bandwidth with possible values of 1, 2, 3, 2 forsystem bandwidths of 1.4 MHz, 3-5 MHz, 10 MHz, >10 MHz, respectively. AWTRU may assume that the channel over which a symbol on a demodulationreference signal antenna port is conveyed in a first PRB within a PRGcan be inferred from the channel over which another symbol on the samedemodulation reference signal antenna port is conveyed in a second PRBwithin the same PRG. In another example, a WTRU may assume that a sameprecoder is use for a demodulation reference signal antenna port in afirst PRB within a PRG and the same demodulation reference signalantenna port in a second PRB within the same PRG. Hereafter, PRB, RB,and virtual RB (VRB) may be interchangeably used.

In LTE, resource block group (RBGs) may be utilized to divide availableresource blocks into multiple groups for allocation purposes. The numberof resource block in a RBG is also function of the system bandwidth withpossible values of 1, 2, 3, 4 for the system bandwidths of 1.4 MHz, 3-5MHz, 10 MHz, >10 MHz, respectively.

In NR, frequency selective precoding may be improved over LTE, forexample, by having more flexibility in choosing precoding resolution. InLTE, the values from which to select the PRB and the PRG (“PRB and PRGsizes”) are very restricted, and precoding operation is applied on thespecific PRB and PRG sizes. While such approach has some benefits interms of feedback overhead, it may not be sufficient in harnessing thefrequency selectivity of the channel.

An alternative approach may be to carry out frequency selectiveprecoding at a resolution finer than the precoding resolution of LTE toenhance MIMO performance. Assuming LTE-like WTRU-specific and/ordemodulation reference signals (collectively “DMRSs”) along withprecoding procedures and codebooks, adopting a higher resolution forfrequency selective precoding may lead to significant challenges forchannel estimation. Due to potential abrupt transitions between selectedadjacent precoders, there will be discontinuities on the effectivechannel. Therefore, a wideband channel estimation might not be possibleleading to either some distortion or poor channel estimation.

In phase-continuous precoding, adjacent precoders may be designed to becontinuous in phase to allow for channel estimation smoothing regardlessof whether reference symbols are precoded (or not). Some of the proposedmethods to perform phase-continuous precoding include time-domainpruning and filtering based on DFT/IDFT processing to ensure phasecontinuity (see, e.g., Qualcomm Incorporated, “Discussion on phasecontinuity and PRB bundling”, 3GPP Tdoc R1-1612045, 3GPP TSG-RAN WG1Meeting #87, Reno, USA, Nov. 14-18, 2016; hereinafter “[1]”); and (ii)frequency smoothed beamforming using a smoothed singular valuedecomposition (SVD), involving finite impulse response (FIR) filteringof nearest adjacent subcarriers, or orthogonal iteration based method togenerate eigenvectors.

However, with precoded DMRS, the reference signal in adjacent resourcesmay be modified by different precoders. This prevents averaging ofchannel estimates across the resources and reduces the accuracy of thechannel estimate. Accordingly, precoding and precoder mechanisms areneeded to allow smooth transition between adjacent precoders.

In addition to design of continuous-phase precoding, informationexchange may be needed to allow both a WTRU and a base station (e.g., agNB) to be aware of respective transmitters and receivers capabilities,and/or to inform one another of the use of phase-continuous precoding soas to enable the respective receiver to implement channel estimationsmoothing.

High resolution frequency selective precoding may be applicable to DLand UL MIMO operation. Hence, procedures and support mechanisms areneeded to enable implementation of such high resolution frequencyselective precoding.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the detailed descriptionbelow, given by way of example in conjunction with drawings appendedhereto. Figures in such drawings, like the detailed description, areexamples. As such, the Figures and the detailed description are not tobe considered limiting, and other equally effective examples arepossible and likely. Furthermore, like reference numerals (“ref.”) inthe Figures indicate like elements, and wherein:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A according to an embodiment;

FIG. 1C is a system diagram illustrating an example radio access network(RAN) and an example core network (CN) that may be used within thecommunications system illustrated in FIG. 1A according to an embodiment;

FIG. 1D is a system diagram illustrating an example RAN and an exampleCN that may be used within the communications system illustrated in FIG.1A according to an embodiment;

FIG. 2 illustrates an example communications system in which embodimentsmay be practiced or implemented;

FIG. 3 is a flow chart illustrating a representative procedure forperforming phase-continuous precoding using cyclic delay diversity(CDD).

FIG. 4 is a graph illustrating a capacity comparison of adaptive CDDprecoding with other precoding mechanisms;

FIG. 5 includes two graphs illustrating distortion of edge elements of atime-domain smoothing precoder;

FIG. 6 is a flow chart illustrating a representative procedure forperforming phase-continuous precoding with non-zero edge smoothing;

FIG. 7 illustrates an example of phase-continuous precoding withnon-zero edge smoothing;

FIG. 8 includes two graphs illustrating a performance comparison ofphase-continuous precoding with non-zero edge smoothing and otherprecoding methods;

FIG. 9 is a flow chart illustrating a representative procedure forperforming phase-continuous precoding with a phase transition region;

FIG. 10 illustrates an example of phase-continuous precoding with phasetransition regions;

FIG. 11 is a flow chart illustrating a representative procedure forperforming phase-continuous precoding with one or more phase transitionregions;

FIGS. 12-14 are flow charts illustrating representative procedures foruse in connection with phase-continuous precoding;

FIG. 15 is a block diagram illustrating example frequency selectiveprecoding for multiple subband transmission;

FIG. 16 is a block diagram illustrating example frequency selectiveprecoding for localized scheduling with various bandwidth components;

FIG. 17 is a block diagram illustrating example frequency selectiveprecoding for localized scheduling with various bandwidth components;

FIG. 18 is a flow chart illustrating a representative procedure for usein connection with phase-continuous precoding;

FIG. 19 illustrates an example transmit precoding matrix indices (TPMI)indication mechanism with supplementary mid-band TPMI information;

FIGS. 20-21 are flow charts illustrating representative procedures foruse in connection with phase-continuous precoding;

FIG. 22 is a block diagram illustrating example frequency selectiveprecoding with sub-band precoders;

FIG. 23 is a block diagram illustrating example frequency selectiveprecoding based on using transmit precoding matrix indices of primarysubbands; and

FIG. 24 is a block diagram illustrating example frequency selectiveprecoding based on using transmit precoding matrix indices of primarysubbands.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth to provide a thorough understanding of embodiments and/or examplesdisclosed herein. However, it will be understood that such embodimentsand examples may be practiced without some or all of the specificdetails set forth herein. In other instances, well-known methods,procedures, components and circuits have not been described in detail,so as not to obscure the following description. Further, embodiments andexamples not specifically described herein may be practiced in lieu of,or in combination with, the embodiments and other examples described,disclosed or otherwise provided explicitly, implicitly and/or inherently(collectively “provided”) herein.

Example Communications System

The methods, apparatuses and systems provided herein are well-suited forcommunications involving both wired and wireless networks. Wirednetworks are well-known. An overview of various types of wirelessdevices and infrastructure is provided with respect to FIGS. 1A-1D,where various elements of the network may utilize, perform, be arrangedin accordance with and/or be adapted and/or configured for the methods,apparatuses and systems provided herein.

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. Examplecommunications system 100 is provided for the purpose of illustrationonly and is not limiting of the disclosed embodiments. Thecommunications system 100 may be a multiple access system that providescontent, such as voice, data, video, messaging, broadcast, etc., tomultiple wireless users. The communications system 100 may enablemultiple wireless users to access such content through the sharing ofsystem resources, including wireless bandwidth. For example, thecommunications systems 100 may employ one or more channel accessmethods, such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail (ZT)unique-word (UW) discreet Fourier transform (DFT) spread OFDM (ZT UWDTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM,filter bank multicarrier (FBMC), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104/113, a core network (CN) 106/115, a publicswitched telephone network (PSTN) 108, the Internet 110, and othernetworks 112, though it will be appreciated that the disclosedembodiments contemplate any number of WTRUs, base stations, networks,and/or network elements. Each of the WTRUs 102 a, 102 b, 102 c, 102 dmay be any type of device configured to operate and/or communicate in awireless environment. By way of example, the WTRUs 102 a, 102 b, 102 c,102 d, any of which may be referred to as a “station” and/or a “STA”,may be configured to transmit and/or receive wireless signals and mayinclude (or be) a user equipment (UE), a mobile station, a fixed ormobile subscriber unit, a subscription-based unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a smartphone, a laptop, anetbook, a personal computer, a wireless sensor, a hotspot or Mi-Fidevice, an Internet of Things (IoT) device, a watch or other wearable, ahead-mounted display (HMD), a vehicle, a drone, a medical device andapplications (e.g., remote surgery), an industrial device andapplications (e.g., a robot and/or other wireless devices operating inan industrial and/or an automated processing chain contexts), a consumerelectronic device, a device operating on commercial and/or industrialwireless networks, and the like. Any of the WTRUs 102 a, 102 b, 102 cand 102 d may be interchangeably referred to as a UE.

The communications systems 100 may also include a base station 114 aand/or a base station 114 b. Each of the base stations 114 a, 114 b maybe any type of device configured to wirelessly interface with at leastone of the WTRUs 102 a, 102 b, 102 c, 102 d, e.g., to facilitate accessto one or more communication networks, such as the CN 106/115, theInternet 110, and/or the networks 112. By way of example, the basestations 114 a, 114 b may be any of a base transceiver station (BTS), aNode-B (NB), an eNode-B (eNB), a Home Node-B (HNB), a Home eNode-B(HeNB), a gNode-B (gNB), a NR Node-B (NR NB), a site controller, anaccess point (AP), a wireless router, and the like. While the basestations 114 a, 114 b are each depicted as a single element, it will beappreciated that the base stations 114 a, 114 b may include any numberof interconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 104/113, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals on one or morecarrier frequencies, which may be referred to as a cell (not shown).These frequencies may be in licensed spectrum, unlicensed spectrum, or acombination of licensed and unlicensed spectrum. A cell may providecoverage for a wireless service to a specific geographical area that maybe relatively fixed or that may change over time. The cell may furtherbe divided into cell sectors. For example, the cell associated with thebase station 114 a may be divided into three sectors. Thus, in oneembodiment, the base station 114 a may include three transceivers, i.e.,one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and mayutilize multiple transceivers for each or any sector of the cell. Forexample, beamforming may be used to transmit and/or receive signals indesired spatial directions.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet(UV), visible light, etc.). The air interface 116 may be establishedusing any suitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104/113 and the WTRUs 102 a,102 b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 115/116/117 using wideband CDMA (WCDMA).WCDMA may include communication protocols such as High-Speed PacketAccess (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-SpeedDownlink Packet Access (HSDPA) and/or High-Speed Uplink Packet Access(HSUPA).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as Evolved UMTS TerrestrialRadio Access (E-UTRA), which may establish the air interface 116 usingLong Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/orLTE-Advanced Pro (LTE-A Pro).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as NR Radio Access, which mayestablish the air interface 116 using New Radio (NR).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement multiple radio access technologies. For example, thebase station 114 a and the WTRUs 102 a, 102 b, 102 c may implement LTEradio access and NR radio access together, for instance using dualconnectivity (DC) principles. Thus, the air interface utilized by WTRUs102 a, 102 b, 102 c may be characterized by multiple types of radioaccess technologies and/or transmissions sent to/from multiple types ofbase stations (e.g., an eNB and a gNB).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.11 (i.e.,Wireless Fidelity (Wi-Fi), IEEE 802.16 (i.e., Worldwide Interoperabilityfor Microwave Access (WiMAX)), CDMA2000, CDMA2000 1x, CDMA2000 EV-DO,Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), InterimStandard 856 (IS-856), Global System for Mobile communications (GSM),Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and thelike.

The base station 114 b in FIG. 1A may be a wireless router, Home Node-B,Home eNode-B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, an industrialfacility, an air corridor (e.g., for use by drones), a roadway, and thelike. In an embodiment, the base station 114 b and the WTRUs 102 c, 102d may implement a radio technology such as IEEE 802.11 to establish awireless local area network (WLAN). In an embodiment, the base station114 b and the WTRUs 102 c, 102 d may implement a radio technology suchas IEEE 802.15 to establish a wireless personal area network (WPAN). Inan embodiment, the base station 114 b and the WTRUs 102 c, 102 d mayutilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A,LTE-A Pro, NR, etc.) to establish any of a small cell, picocell orfemtocell. As shown in FIG. 1A, the base station 114 b may have a directconnection to the Internet 110. Thus, the base station 114 b may not berequired to access the Internet 110 via the CN 106/115.

The RAN 104/113 may be in communication with the CN 106/115, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. The data may have varying qualityof service (QoS) requirements, such as differing throughputrequirements, latency requirements, error tolerance requirements,reliability requirements, data throughput requirements, mobilityrequirements, and the like. The CN 106/115 may provide call control,billing services, mobile location-based services, pre-paid calling,Internet connectivity, video distribution, etc., and/or performhigh-level security functions, such as user authentication. Although notshown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or theCN 106/115 may be in direct or indirect communication with other RANsthat employ the same RAT as the RAN 104/113 or a different RAT. Forexample, in addition to being connected to the RAN 104/113, which may beutilizing an NR radio technology, the CN 106/115 may also be incommunication with another RAN (not shown) employing any of a GSM, UMTS,CDMA 2000, WiMAX, E-UTRA, or Wi-Fi radio technology.

The CN 106/115 may also serve as a gateway for the WTRUs 102 a, 102 b,102 c, 102 d to access the PSTN 108, the Internet 110, and/or othernetworks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another CN connected to one or more RANs, which mayemploy the same RAT as the RAN 104/114 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities (e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks). For example, the WTRU 102 c shown in FIG. 1A may be configuredto communicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. Example WTRU 102 isprovided for the purpose of illustration only and is not limiting of thedisclosed embodiments. As shown in FIG. 1B, the WTRU 102 may include aprocessor 118, a transceiver 120, a transmit/receive element 122, aspeaker/microphone 124, a keypad 126, a display/touchpad 128,non-removable memory 130, removable memory 132, a power source 134, aglobal positioning system (GPS) chipset 136, and other peripherals 138,among others. It will be appreciated that the WTRU 102 may include anysub-combination of the foregoing elements while remaining consistentwith an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together, e.g., in an electronicpackage or chip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in an embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In an embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In an embodiment,the transmit/receive element 122 may be configured to transmit andreceive both RF and light signals. It will be appreciated that thetransmit/receive element 122 may be configured to transmit and/orreceive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. For example, the WTRU 102 may employ MIMOtechnology. Thus, in one embodiment, the WTRU 102 may include two ormore transmit/receive elements 122 (e.g., multiple antennas) fortransmitting and receiving wireless signals over the air interface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as NR and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(e.g., for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, a virtual reality and/or augmented reality (VR/AR) device, anactivity tracker, and the like. The peripherals 138 may include one ormore sensors, the sensors may be one or more of a gyroscope, anaccelerometer, a hall effect sensor, a magnetometer, an orientationsensor, a proximity sensor, a temperature sensor, a time sensor; ageolocation sensor; an altimeter, a light sensor, a touch sensor, amagnetometer, a barometer, a gesture sensor, a biometric sensor, and/ora humidity sensor.

The WTRU 102 may include a full duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for both the UL (e.g., for transmission) anddownlink (e.g., for reception) may be concurrent and/or simultaneous.The full duplex radio may include an interference management unit toreduce and or substantially eliminate self-interference via eitherhardware (e.g., a choke) or signal processing via a processor (e.g., aseparate processor (not shown) or via processor 118). In an embodiment,the WTRU 102 may include a half-duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for either the UL (e.g., for transmission) or thedownlink (e.g., for reception)).

FIG. 1C is a system diagram of the RAN 104 and the CN 106 according toanother embodiment. As noted above, the RAN 104 may employ an E-UTRAradio technology to communicate with the WTRUs 102 a, 102 b, and 102 cover the air interface 116. The RAN 104 may also be in communicationwith the CN 106.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In an embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 160 a, 160 b, and 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink (UL) and/or downlink (DL), and the like. As shown in FIG.1C, the eNode-Bs 160 a, 160 b, 160 c may communicate with one anotherover an X2 interface.

The core network 106 shown in FIG. 1C may include a mobility managementgateway (MME) 162, a serving gateway (SGW) 164, and a packet datanetwork (PDN) gateway 166. While each of the foregoing elements aredepicted as part of the CN 106, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than theCN operator.

The MME 162 may be connected to each of the eNode-Bs 160 a, 160 b, and160 c in the RAN 104 via an S1 interface and may serve as a controlnode. For example, the MME 162 may be responsible for authenticatingusers of the WTRUs 102 a, 102 b, 102 c, bearer activation/deactivation,selecting a particular serving gateway during an initial attach of theWTRUs 102 a, 102 b, 102 c, and the like. The MME 162 may also provide acontrol plane function for switching between the RAN 104 and other RANs(not shown) that employ other radio technologies, such as GSM or WCDMA.

The SGW 164 may be connected to each of the eNode-Bs 160 a, 160 b, 160 cin the RAN 104 via the S1 interface. The SGW 164 may generally route andforward user data packets to/from the WTRUs 102 a, 102 b, 102 c. The SGW164 may also perform other functions, such as anchoring user planesduring inter-eNode-B handovers, triggering paging when DL data isavailable for the WTRUs 102 a, 102 b, 102 c, managing and storingcontexts of the WTRUs 102 a, 102 b, 102 c, and the like.

The SGW 164 may also be connected to the PDN gateway 166, which mayprovide the WTRUs 102 a, 102 b, 102 c with access to packet-switchednetworks, such as the Internet 110, to facilitate communications betweenthe WTRUs 102 a, 102 b, 102 c and IP-enabled devices.

The CN 106 may facilitate communications with other networks. Forexample, the CN 106 may provide the WTRUs 102 a, 102 b, 102 c withaccess to circuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. For example, the CN 106 may include,or may communicate with, an IP gateway (e.g., an IP multimedia subsystem(IMS) server) that serves as an interface between the CN 106 and thePSTN 108. In addition, the CN 106 may provide the WTRUs 102 a, 102 b,102 c with access to the other networks 112, which may include otherwired or wireless networks that are owned and/or operated by otherservice providers.

Although the WTRU is described in FIGS. 1A-1D as a wireless terminal, itis contemplated that in certain representative embodiments that such aterminal may use (e.g., temporarily or permanently) wired communicationinterfaces with the communication network.

In representative embodiments, the other network 112 may be a WLAN.

A WLAN in Infrastructure Basic Service Set (BSS) mode may have an AccessPoint (AP) for the BSS and one or more stations (STAs) associated withthe AP. The AP may have an access or an interface to a DistributionSystem (DS) or another type of wired/wireless network that carriestraffic in to and/or out of the BSS. Traffic to STAs that originatesfrom outside the BSS may arrive through the AP and may be delivered tothe STAs. Traffic originating from STAs to destinations outside the BSSmay be sent to the AP to be delivered to respective destinations.Traffic between STAs within the BSS may be sent through the AP, forexample, where the source STA may send traffic to the AP and the AP maydeliver the traffic to the destination STA. The traffic between STAswithin a BSS may be considered and/or referred to as peer-to-peertraffic. The peer-to-peer traffic may be sent between (e.g., directlybetween) the source and destination STAs with a direct link setup (DLS).In certain representative embodiments, the DLS may use an 802.11e DLS oran 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS)mode may not have an AP, and the STAs (e.g., all of the STAs) within orusing the IBSS may communicate directly with each other. The IBSS modeof communication may sometimes be referred to herein as an “ad-hoc” modeof communication.

When using the 802.11ac infrastructure mode of operation or a similarmode of operations, the AP may transmit a beacon on a fixed channel,such as a primary channel. The primary channel may be a fixed width(e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling.The primary channel may be the operating channel of the BSS and may beused by the STAs to establish a connection with the AP. In certainrepresentative embodiments, Carrier Sense Multiple Access with CollisionAvoidance (CSMA/CA) may be implemented, for example in in 802.11systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, maysense the primary channel. If the primary channel is sensed/detectedand/or determined to be busy by a particular STA, the particular STA mayback off. One STA (e.g., only one station) may transmit at any giventime in a given BSS.

High Throughput (HT) STAs may use a 40 MHz wide channel forcommunication, for example, via a combination of the primary 20 MHzchannel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHzwide channel.

Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz,and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may beformed by combining contiguous 20 MHz channels. A 160 MHz channel may beformed by combining 8 contiguous 20 MHz channels, or by combining twonon-contiguous 80 MHz channels, which may be referred to as an 80+80configuration. For the 80+80 configuration, the data, after channelencoding, may be passed through a segment parser that may divide thedata into two streams. Inverse Fast Fourier Transform (IFFT) processing,and time domain processing, may be done on each stream separately. Thestreams may be mapped on to the two 80 MHz channels, and the data may betransmitted by a transmitting STA. At the receiver of the receiving STA,the above described operation for the 80+80 configuration may bereversed, and the combined data may be sent to a Medium Access Control(MAC).

Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. Thechannel operating bandwidths, and carriers, are reduced in 802.11af and802.11ah relative to those used in 802.11n, and 802.11ac. 802.11afsupports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space(TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and16 MHz bandwidths using non-TVWS spectrum. According to a representativeembodiment, 802.11ah may support Meter Type Control/Machine-TypeCommunications (MTC), such as MTC devices in a macro coverage area. MTCdevices may have certain capabilities, for example, limited capabilitiesincluding support for (e.g., only support for) certain and/or limitedbandwidths. The MTC devices may include a battery with a battery lifeabove a threshold (e.g., to maintain a very long battery life).

WLAN systems, which may support multiple channels, and channelbandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include achannel which may be designated as the primary channel. The primarychannel may have a bandwidth equal to the largest common operatingbandwidth supported by all STAs in the BSS. The bandwidth of the primarychannel may be set and/or limited by a STA, from among all STAs inoperating in a BSS, which supports the smallest bandwidth operatingmode. In the example of 802.11ah, the primary channel may be 1 MHz widefor STAs (e.g., MTC type devices) that support (e.g., only support) a 1MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes.Carrier sensing and/or Network Allocation Vector (NAV) settings maydepend on the status of the primary channel. If the primary channel isbusy, for example, due to a STA (which supports only a 1 MHz operatingmode), transmitting to the AP, the entire available frequency bands maybe considered busy even though a majority of the frequency bands remainsidle and may be available.

In the United States, the available frequency bands, which may be usedby 802.11ah, are from 902 MHz to 928 MHz. In Korea, the availablefrequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the availablefrequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidthavailable for 802.11ah is 6 MHz to 26 MHz depending on the country code.

FIG. 1D is a system diagram illustrating the RAN 113 and the CN 115according to an embodiment. As noted above, the RAN 113 may employ an NRradio technology to communicate with the WTRUs 102 a, 102 b, 102 c overthe air interface 116. The RAN 113 may also be in communication with theCN 115.

The RAN 113 may include gNBs 180 a, 180 b, 180 c, though it will beappreciated that the RAN 113 may include any number of gNBs whileremaining consistent with an embodiment. The gNBs 180 a, 180 b, 180 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the gNBs 180 a, 180 b, 180 c may implement MIMO technology. For example,gNBs 180 a, 180 b may utilize beamforming to transmit signals to and/orreceive signals from the gNBs 180 a, 180 b, 180 c. Thus, the gNB 180 a,for example, may use multiple antennas to transmit wireless signals to,and/or receive wireless signals from, the WTRU 102 a. In an embodiment,the gNBs 180 a, 180 b, 180 c may implement carrier aggregationtechnology. For example, the gNB 180 a may transmit multiple componentcarriers to the WTRU 102 a (not shown). A subset of these componentcarriers may be on unlicensed spectrum while the remaining componentcarriers may be on licensed spectrum. In an embodiment, the gNBs 180 a,180 b, 180 c may implement Coordinated Multi-Point (CoMP) technology.For example, WTRU 102 a may receive coordinated transmissions from gNB180 a and gNB 180 b (and/or gNB 180 c).

The WTRUs 102 a, 102 b, 102 c may communicate with gNBs 180 a, 180 b,180 c using transmissions associated with a scalable numerology. Forexample, OFDM symbol spacing and/or OFDM subcarrier spacing may vary fordifferent transmissions, different cells, and/or different portions ofthe wireless transmission spectrum. The WTRUs 102 a, 102 b, 102 c maycommunicate with gNBs 180 a, 180 b, 180 c using subframe or transmissiontime intervals (TTIs) of various or scalable lengths (e.g., containing avarying number of OFDM symbols and/or lasting varying lengths ofabsolute time).

The gNBs 180 a, 180 b, 180 c may be configured to communicate with theWTRUs 102 a, 102 b, 102 c in a standalone configuration and/or anon-standalone configuration. In the standalone configuration, WTRUs 102a, 102 b, 102 c may communicate with gNBs 180 a, 180 b, 180 c withoutalso accessing other RANs (e.g., such as eNode-Bs 160 a, 160 b, 160 c).In the standalone configuration, WTRUs 102 a, 102 b, 102 c may utilizeone or more of gNBs 180 a, 180 b, 180 c as a mobility anchor point. Inthe standalone configuration, WTRUs 102 a, 102 b, 102 c may communicatewith gNBs 180 a, 180 b, 180 c using signals in an unlicensed band. In anon-standalone configuration WTRUs 102 a, 102 b, 102 c may communicatewith/connect to gNBs 180 a, 180 b, 180 c while also communicatingwith/connecting to another RAN such as eNode-Bs 160 a, 160 b, 160 c. Forexample, WTRUs 102 a, 102 b, 102 c may implement DC principles tocommunicate with one or more gNBs 180 a, 180 b, 180 c and one or moreeNode-Bs 160 a, 160 b, 160 c substantially simultaneously. In thenon-standalone configuration, eNode-Bs 160 a, 160 b, 160 c may serve asa mobility anchor for WTRUs 102 a, 102 b, 102 c and gNBs 180 a, 180 b,180 c may provide additional coverage and/or throughput for servicingWTRUs 102 a, 102 b, 102 c.

Each of the gNBs 180 a, 180 b, 180 c may be associated with a particularcell (not shown) and may be configured to handle radio resourcemanagement decisions, handover decisions, scheduling of users in the ULand/or DL, support of network slicing, dual connectivity, interworkingbetween NR and E-UTRA, routing of user plane data towards User PlaneFunction (UPF) 184 a, 184 b, routing of control plane informationtowards Access and Mobility Management Function (AMF) 182 a, 182 b, andthe like. As shown in FIG. 1D, the gNBs 180 a, 180 b, 180 c maycommunicate with one another over an Xn interface.

The CN 115 shown in FIG. 1D may include at least one AMF 182 a, 182 b,at least one UPF 184 a, 184 b, at least one Session Management Function(SMF) 183 a, 183 b, and possibly at least one Data Network (DN) 185 a,185 b. While each of the foregoing elements are depicted as part of theCN 115, it will be appreciated that any of these elements may be ownedand/or operated by an entity other than the CN operator.

The AMF 182 a, 182 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N2 interface and may serve as acontrol node. For example, the AMF 182 a, 182 b may be responsible forauthenticating users of the WTRUs 102 a, 102 b, 102 c, support fornetwork slicing (e.g., handling of different packet data unit (PDU)sessions with different requirements), selecting a particular SMF 183 a,183 b, management of the registration area, termination of NASsignaling, mobility management, and the like. Network slicing may beused by the AMF 182 a, 182 b, e.g., to customize CN support for WTRUs102 a, 102 b, 102 c based on the types of services being utilized WTRUs102 a, 102 b, 102 c. For example, different network slices may beestablished for different use cases such as services relying onultra-reliable low latency (URLLC) access, services relying on enhancedmassive mobile broadband (eMBB) access, services for MTC access, and/orthe like. The AMF 162 may provide a control plane function for switchingbetween the RAN 113 and other RANs (not shown) that employ other radiotechnologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP accesstechnologies such as Wi-Fi.

The SMF 183 a, 183 b may be connected to an AMF 182 a, 182 b in the CN115 via an N11 interface. The SMF 183 a, 183 b may also be connected toa UPF 184 a, 184 b in the CN 115 via an N4 interface. The SMF 183 a, 183b may select and control the UPF 184 a, 184 b and configure the routingof traffic through the UPF 184 a, 184 b. The SMF 183 a, 183 b mayperform other functions, such as managing and allocating UE IP address,managing PDU sessions, controlling policy enforcement and QoS, providingdownlink data notifications, and the like. A PDU session type may beIP-based, non-IP based, Ethernet-based, and the like.

The UPF 184 a, 184 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N3 interface, which may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, e.g., to facilitate communications between theWTRUs 102 a, 102 b, 102 c and IP-enabled devices. The UPF 184, 184 b mayperform other functions, such as routing and forwarding packets,enforcing user plane policies, supporting multi-homed PDU sessions,handling user plane QoS, buffering downlink packets, providing mobilityanchoring, and the like.

The CN 115 may facilitate communications with other networks. Forexample, the CN 115 may include, or may communicate with, an IP gateway(e.g., an IP multimedia subsystem (IMS) server) that serves as aninterface between the CN 115 and the PSTN 108. In addition, the CN 115may provide the WTRUs 102 a, 102 b, 102 c with access to the othernetworks 112, which may include other wired and/or wireless networksthat are owned and/or operated by other service providers. In oneembodiment, the WTRUs 102 a, 102 b, 102 c may be connected to a localData Network (DN) 185 a, 185 b through the UPF 184 a, 184 b via the N3interface to the UPF 184 a, 184 b and an N6 interface between the UPF184 a, 184 b and the DN 185 a, 185 b.

In view of FIGS. 1A-1D, and the corresponding description of FIGS.1A-1D, one or more, or all, of the functions described herein withregard to any of: WTRUs 102 a-d, base stations 114 a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180 a-c, AMFs 182 a-b, UPFs 184a-b, SMFs 183 a-b, DNs 185 a-b, and/or any other element(s)/device(s)described herein, may be performed by one or more emulationelements/devices (not shown). The emulation devices may be one or moredevices configured to emulate one or more, or all, of the functionsdescribed herein. For example, the emulation devices may be used to testother devices and/or to simulate network and/or WTRU functions.

The emulation devices may be designed to implement one or more tests ofother devices in a lab environment and/or in an operator networkenvironment. For example, the one or more emulation devices may performthe one or more, or all, functions while being fully or partiallyimplemented and/or deployed as part of a wired and/or wirelesscommunication network in order to test other devices within thecommunication network. The one or more emulation devices may perform theone or more, or all, functions while being temporarilyimplemented/deployed as part of a wired and/or wireless communicationnetwork. The emulation device may be directly coupled to another devicefor purposes of testing and/or may performing testing using over-the-airwireless communications.

The one or more emulation devices may perform the one or more, includingall, functions while not being implemented/deployed as part of a wiredand/or wireless communication network. For example, the emulationdevices may be utilized in a testing scenario in a testing laboratoryand/or a non-deployed (e.g., testing) wired and/or wirelesscommunication network in order to implement testing of one or morecomponents. The one or more emulation devices may be test equipment.Direct RF coupling and/or wireless communications via RF circuitry(e.g., which may include one or more antennas) may be used by theemulation devices to transmit and/or receive data.

FIG. 2 illustrates an example communications system 200 in whichembodiments may be practiced or implemented. The communications system200 is provided for the purpose of illustration only and is not limitingof disclosed embodiments. As shown in FIG. 2, the communications system200 includes a base station 202 and WTRUs 204 a, 204 b. As would beunderstood by a person of skill in the art, the communications system200 may include additional elements not shown in FIG. 2.

The base station 202 may be any of the base stations 114 (FIG. 1A),eNode-Bs 160 (FIG. 1C) and gNBs 180 (FIG. 1D), for example. The basestation 202 may include functionality similar to, and/or different from,the base stations 114, eNode-Bs 160 and gNBs 180, as well. For example,the base station 202 may include functionality to support features of 5Gand to implement the procedures, techniques, etc. included herein.

The base station 202 may be configured for small cell operation and/ordeployment. The base station 202 may be configured to support any ofcentimeter wave (cmW) and millimeter wave (mmW) operation. Forsimplicity of exposition, the term “xmW” may be used herein to refer toany of cmW and mmW. The base station 202 may be additionally and/oralternatively configured to support various (e.g., all or some)functionality and/or features for small cell operation and/or deploymentas specified in 3GPP Release 12. In this regard, the base station 202may be capable of operating an xmW air interface in parallel,simultaneously and/or otherwise in connection with an LTE, LTE-A orlike-type (collectively “LTE”) air interface. The base station 202 maybe equipped with at least one of various advanced antenna configurationsand beamforming techniques, such as those that may allow the basestation 202 to simultaneously transmit LTE downlink channels in a widebeam pattern and xmW channels in one or more narrow beam patterns. Thebase station 202 may also be configured to utilize an LTE uplinkconfiguration adapted with features and procedures (e.g., those detailedherein) to support WTRUs that lack, or do not use their, xmW uplinktransmission capabilities.

Each of the WTRUs 204 a, 204 b may be any of the WTRUs 102 (FIGS.1A-1D), for example. Each of the WTRUs 204 a, 204 b may includefunctionality similar to, and/or different from, the WTRUs 102, as well.The WTRUs 204 a, 204 b may include functionality to support features of5G and to implement the procedures, techniques, etc. included herein.For simplicity of exposition, when “WTRU 204” is used herein, it mayrefer to any of the WTRUs 204 a, 204 b.

Each of the WTRUs 204 a, 204 b may be configured to support xmWoperation. The WTRUs 204 a, 204 b may be further configured to supportvarious (e.g., all or some) functionality and/or features for userequipment operation and/or deployment as specified in 3GPP Release 12.Each of the WTRUs 204 a, 204 b may be capable of operating LTE and xmWair interfaces in parallel, simultaneously and/or otherwise inconnection with each other. Each of the WTRUs 204 a, 204 b may have twosets of antennas and accompanying RF chains; one configured foroperating in a LTE band and the other configured for operating in a xmWfrequency band. However, the present disclosure is not limited thereto,and a WTRU may have any number of sets of antennas and accompanying RFchains. Each of the WTRUs 204 a, 204 b may include one or more basebandprocessors, and the baseband processors may include separate, or atleast partially combined, functionality for baseband processing of theLTE frequency band and the xmW frequency band. The baseband processingfunctions may share hardware blocks for the xmW and LTE air interfaces,for example.

As used herein the term(s) “effective channel” may refer to a product ofprecoding and the actual wireless channel. Also, as used herein belowthe term(s) “per-tone precoding” may imply a phase-continuous precodingoperation and vice-versa.

Overview

This disclosure is drawn, inter alia, to methods, apparatuses, systems,devices, and computer program products directed to phase-continuousfrequency selective multiple-input multiple-output (MIMO) precoding. Themethods may include any of (i) performing phase-continuous precodingusing cyclic delay diversity (CDD), (ii) performing phase-continuousprecoding with non-zero edge smoothing, (iii) performingphase-continuous precoding with phase transition region, and (iv)performing phase-continuous precoding for non-contiguous transmission.

In an embodiment, performing phase-continuous precoding using CDD mayinclude any of determining, for a plurality of precoding resource sets(PRSs), a respective plurality of CDD-based precoding matrices;precoding a first PRS of the plurality of PRSs using (at least) therespective first CDD-based precoding matrix of the plurality ofCDD-based precoding matrices and a first matrix adapted to provide aninitial phase for precoding; and precoding a second PRS of the pluralityof PRSs using (at least) the respective second CDD-based precodingmatrix of the plurality of CDD-based precoding matrices and a secondmatrix adapted to provide phase continuity from the first precoded PRS.

Among the methods is first a method that may be implemented in a firstdevice configured to communicate with a second device, and that mayinclude informing a first device of capabilities of a second device; anddetermining whether the second device supports phase-continuousprecoding based on capabilities of the second device. The first andsecond devices may be a base station and a wireless transmit/receiverunit (WTRU) (or vice versa), respectively.

Among the methods is a second method that may be implemented in a firstdevice configured to communicate with a second device, and that mayinclude informing, by the first device, that a specific transmission isusing phase-continuous precoders in the control channel. The first andsecond devices may be a base station and a WTRU (or vice versa),respectively.

Among the methods is a third method that that may include, formulti-user transmission, each WTRU of a plurality of WTRUs signaling abase station whether it is using phase-continuous precoding.

Among the methods is a fourth method that that may include transmittinga single bit to indicate per-tone precoding vs wideband precoding on acontrol channel. Among the methods is a fifth method that that mayinclude transmitting information to indicate per-tone precoding vswideband precoding implicitly by embedding the information into ademodulation reference signal (DMRS).

Among the methods is a sixth method that that may include receiving asize of a precoding resource block group (PRG); and determining, basedon the size of the PRG, whether per-tone precoding (or widebandprecoding) is activated. In an embodiment, the size of the PRG is orcorresponds to a size of a scheduling grant.

Among the methods is a seventh method that that may include decoding acontrol channel at a device; and on discovering that a data channel isphase-continuously precoded, implementing, at the device, channelestimation smoothing.

Among the methods is an eighth method that that may include blindlyestimating, at a device, whether a data channel is precoded using phasecontinuous precoders; and on failure to decode the data channel,decoding the data channel assuming no phase-continuous precoding.

Among the methods is a ninth method that may be implemented in a firstdevice configured to communicate with a second device, and may includetransmitting, to the second device, signaling indicating transmitprecoding information for (i) a plurality of subbands of a firstbandwidth assigned to the second device, and (ii) one or more secondbandwidths. The signaling may include a resource allocation defining thefirst bandwidth. The signaling may be a grant, for example.Alternatively, the signaling may include a combination of a grant andhigher layer signaling.

Among the methods is a tenth method that may be implemented in a firstdevice configured to communicate with a second device, and may includetransmitting, to the second device, signaling indicating transmitprecoding information for (i) a plurality of subbands of a firstbandwidth assigned to the second device, and (ii) one or more secondbandwidths; and transmitting a grant including a resource allocationdefining a third bandwidth including at least one segment of the one ormore second bandwidths.

In an any of the methods provided herein, the transmit precodinginformation may include one or more transmit precoding informationindications. the one or more transmit precoding information indicationscomprises one or more transmit precoding matrix indices (TPMI)indications. Alternatively, the transmit precoding information mayinclude one or more sounding reference signal (SRS) resource indicators(SRIs). The SRIs may include one or more (e.g., respective) transmitprecoding information indications. Each SRI may associate one or moreSRS ports to one of the transmit precoding information indications. EachSRI may include an indication of one or more SRS ports and one of thetransmit precoding information indications. The transmit precodinginformation indications may correspond to any of a single stage codebookand a dual stage codebook.

The transmit precoding information may include one or more firsttransmit precoding information indications for the plurality of subbandsand one or more second transmit precoding information indications forthe one or more second bandwidths. The first transmit precodinginformation indications may be one or more TPMI indications, and thesecond transmit precoding information indications may include one ormore TPMI indications. Alternatively, the transmit precoding informationmay include one or more first SRIs and one or more second SRIs. Thefirst SRIs may include one or more first transmit precoding informationindications for the plurality of subbands. The second SRIs may includeone or more second transmit precoding information indications for theone or more second bandwidths. Each of the first SRIs may associate oneor more SRS ports to one of the first transmit precoding informationindications. Each of the second SRIs may associate one or more SRS portsto one of the second transmit precoding information indications. Each ofthe first SRIs may include an indication of one or more SRS ports andone of the first transmit precoding information indications. Each of thesecond SRIs may include an indication of one or more SRS ports and oneof the one or more second transmit precoding information indications.

The first transmit precoding information indications may be updated at adifferent rate than the second transmit precoding informationindications. For example, the first transmit precoding informationindications may be updated more frequently than the second transmitprecoding information indications.

The first SRIs may be updated at a different rate than the second SRIs.For example, the first SRIs may be updated more frequently than the oneor more second SRIs.

The first transmit precoding information indications may correspond to adual-stage codebook. The second transmit precoding informationindications may correspond to a single-stage codebook.

In an embodiment, the first transmit precoding information indicationsmay correspond to one or more (e.g., respective) narrow-band precodercomponents and the second transmit precoding information indications maycorrespond to one or more (e.g., respective) mid-band precodercomponents. In an embodiment, the first transmit precoding informationindications may correspond to one or more (e.g., respective) narrow-bandprecoder components, and the second transmit precoding informationindications may correspond to one or more (e.g., respective) wide-bandprecoder components.

In an embodiment, the plurality of subbands may have a respectiveplurality of bandwidths, and the first bandwidth may span the pluralityof bandwidths. The plurality of subbands may be contiguous ornon-contiguous. The plurality of subbands may correspond to a selectiveset of (e.g., best M) subbands of the first bandwidth.

Among the methods is a tenth method that may be implemented in a firstdevice configured to communicate with a second device, and may includetransmitting, to the second device in connection with a first of aplurality of grants, transmit precoding information for (i) a pluralityof subbands of a first bandwidth assigned to the second device, and (ii)one or more second bandwidths; transmitting, to the second device inconnection with a second of a plurality of grants, transmit precodinginformation for (i) a plurality of subbands of a third bandwidthassigned to the second device, and (ii) the one or more secondbandwidths; and transmitting, to the second device in connection with athird of a plurality of grants, transmit precoding information for (i) aplurality of subbands of a fourth bandwidth assigned to the seconddevice, and (ii) one or more fifth bandwidths.

Among the methods is an eleventh method that may be implemented in afirst device configured to communicate with a second device, and mayinclude transmitting, to the second device in connection with a first ofa plurality of grants, one or more first SRIs and one or more secondSRIs, wherein each of the first SRIs may include a first indication ofone or more first SRS ports and first transmit precoding informationassociated with one of a plurality of subbands of a first bandwidthassigned to the second device, and wherein each of the second SRIs mayinclude a second indication of one or more second SRS ports and secondtransmit precoding information associated with one of one or more secondbandwidths; transmitting, to the second device in connection with asecond of a plurality of grants, one or more third SRIs and the secondSRIs, wherein each of the third SRIs comprises a third indication of oneor more third SRS ports and third transmit precoding informationassociated with one of a plurality of subbands of a third bandwidthassigned to the second device; and transmitting, to the second device inconnection with a third of a plurality of grants, one or more fourthSRIs and one or more fifth SRIs, wherein each of the fourth SRIs mayinclude a fourth indication of one or more fourth SRS ports and fourthtransmit precoding information associated with one of a plurality ofsubbands of a fourth bandwidth assigned to the second device, andwherein each of the fifth SRIs may include a fifth indication of one ormore fifth SRS ports and fifth transmit precoding information associatedwith one of one or more fifth bandwidths.

Among the methods is a twelfth method that may be implemented in a firstdevice configured to communicate with a second device, and may includetransmitting, to the second device in connection with a first of aplurality of grants, transmit precoding information for (i) a pluralityof subbands of a first bandwidth assigned to the second device, and (ii)one or more second bandwidths; transmitting, to the second device inconnection with a second of a plurality of grants, transmit precodinginformation for (i) a plurality of subbands of a third bandwidthassigned to the second device, and (ii) the one or more secondbandwidths; and transmitting, to the second device in connection with athird of a plurality of grants, transmit precoding information for (i)the plurality of subbands of third bandwidth assigned to the seconddevice, and (ii) one or more fourth bandwidths.

Among the methods is a thirteenth method that may be implemented in afirst device configured to communicate with a second device, and mayinclude transmitting, to the second device in connection with a first ofa plurality of grants, one or more first SRIs and one or more secondSRIs, wherein each of the first SRIs may include a first indication ofone or more first SRS ports and first transmit precoding informationassociated with one of a plurality of subbands of a first bandwidthassigned to the second device, and wherein each of the second SRIs mayinclude a second indication of one or more second SRS ports and secondtransmit precoding information associated with one of one or more secondbandwidths; transmitting, to the second device in connection with asecond of a plurality of grants, one or more third SRIs and the secondSRIs, wherein each of the third SRIs may include a third indication ofone or more third SRS ports and third transmit precoding informationassociated with one of a plurality of subbands of a third bandwidthassigned to the second device; and transmitting, to the second device inconnection with a third of a plurality of grants, the third SRIs and oneor more fourth SRIs, wherein each of the fourth SRIs may include afourth indication of one or more fourth SRS ports and fourth transmitprecoding information associated with one of one or more fourthbandwidths.

Among the methods is a fourteenth method that may be implemented in afirst device configured to communicate with a second device, and mayinclude transmitting, to the second device, signaling indicatingtransmit precoding information for (i) a plurality of subbands of afirst bandwidth assigned to the second device, and (ii) one or moresecond bandwidths; transmitting, to the second device, signalingindicating transmit precoding information for (i) a plurality ofsubbands of a third bandwidth assigned to the second device, and (ii)the second bandwidths; and transmitting, to the second device, signalingindicating transmit precoding information for (i) a plurality ofsubbands of a fourth bandwidth assigned to the second device, and (ii)one or more fifth bandwidths.

Among the methods is a fifteenth method that may be implemented in afirst device configured to communicate with a second device, and mayinclude transmitting, to the second device, one or more first SRIs andone or more second SRIs, wherein each of the first SRIs may include afirst indication of one or more first SRS ports and first transmitprecoding information associated with one of a plurality of subbands ofa first bandwidth assigned to the second device, and wherein each of thesecond SRIs may include a second indication of one or more second SRSports and second transmit precoding information associated with one ofone or more second bandwidths; transmitting, to the second device, oneor more third SRIs and the one or more second SRIs, wherein each of thethird SRIs may include a third indication of one or more third SRS portsand third transmit precoding information associated with one of aplurality of subbands of a third bandwidth assigned to the seconddevice; and transmitting, to the second device, one or more fourth SRIsand one or more fifth SRIs, wherein each of the fourth SRIs may includea fourth indication of one or more fourth SRS ports and fourth transmitprecoding information associated with one of a plurality of subbands ofa fourth bandwidth assigned to the second device, and wherein each ofthe fifth SRIs comprises a fifth indication of one or more fifth SRSports and fifth transmit precoding information associated with one ofone or more fifth bandwidths.

Among the methods is a sixteenth method that may be implemented in afirst device configured to communicate with a second device, and mayinclude transmitting, to the second device, signaling indicatingtransmit precoding information for (i) a plurality of subbands of afirst bandwidth assigned to the second device, and (ii) one or moresecond bandwidths; transmitting, to the second device, signalingindicating transmit precoding information for (i) a plurality ofsubbands of a third bandwidth assigned to the second device, and (ii)the second bandwidths; and transmitting, to the second device, signalingindicating transmit precoding information for (i) the plurality ofsubbands of a third bandwidth assigned to the second device, and (ii)one or more fourth bandwidths.

Among the methods is a seventeenth method that may be implemented in afirst device configured to communicate with a second device, and mayinclude transmitting, to the second device, one or more first SRIs andone or more second SRIs, wherein each of the first SRIs may include afirst indication of one or more first SRS ports and first transmitprecoding information associated with one of a plurality of subbands ofa first bandwidth assigned to the second device, and wherein each of thesecond SRIs may include a second indication of one or more second SRSports and second transmit precoding information associated with one ofone or more second bandwidths; transmitting, to the second device, oneor more third SRIs and the second SRIs, wherein each of the third SRIsmay include a third indication of one or more third SRS ports and thirdtransmit precoding information associated with one of a plurality ofsubbands of a third bandwidth assigned to the second device; andtransmitting, to the second device, the third SRIs and one or morefourth SRIs, wherein each of the fourth SRIs may include a fourthindication of one or more fourth SRS ports and fourth transmit precodinginformation associated with one of one or more fourth bandwidths.

Also among the methods is an eighteenth method that may be implementedin the second device and may include receiving the signaling from thefirst device. In various embodiments, the eighteenth method may includeany of determining, from the transmit precoding information, a pluralityof precoders corresponding to the plurality of subbands; performingprecoding of assigned resources at the plurality of subbands using theplurality of precoders; determining, from the transmit precodinginformation, a second precoder corresponding to at least one segment ofthe one or more second bandwidths; and performing precoding of theassigned resources at one or more subbands of the first bandwidth otherthan the plurality of subbands using the second precoder; receiving agrant comprising a resource allocation defining a third bandwidthcomprising at least one segment of the second bandwidths; determining,from the transmit precoding information, a third precoder correspondingto the at least one segment; and performing precoding of assignedresources at the at least one segment using the third precoder. Thesecond and third precoders may be the same.

As one skilled in the art will recognize, the second device may carryout methods complementary to the ninth through seventeenth methods usingthe functions of, or akin to, those disclosed in the eighteenth method.

Representative Examples of Phase-Continuous Precoding

Various types of phase-continuous precoding may be used to allow smoothtransition between adjacent precoders. Representative examples of suchphase-continuous precoding may include any of (i) phase-continuousprecoding using CDD, (ii) phase-continuous precoding with non-zero edgesmoothing, (iii) phase-continuous precoding with phase transitionregion, and (iv) phase-continuous precoding for non-contiguoustransmission.

Representative Phase-Continuous Precoding using Cyclic Delay DiversityExample(s)

FIG. 3 is a flow chart illustrating a representative procedure 300 forperforming phase-continuous precoding using CDD. The representativeprocedure 300 may be implemented in a device such as a base station(e.g., any of the base stations 114, eNode-Bs 160, gNBs 180 and basestations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs 204). Therepresentative procedure 300 may be implemented in a device other than abase station and a WTRU as well.

As shown in FIG. 3, the device may determine, for a plurality ofprecoding resource sets (PRSs), a respective plurality of CDD-basedprecoding matrices (302). The device may precode a first PRS of theplurality of PRSs using (at least) the respective first CDD-basedprecoding matrix of the plurality of CDD-based precoding matrices and afirst matrix adapted to provide an initial phase for precoding (304).The device may precode a second PRS of the plurality of PRSs using (atleast) the respective second CDD-based precoding matrix of the pluralityof CDD-based precoding matrices and a second matrix adapted to providephase continuity from the first precoded PRS (306).

In an embodiment, the device may determine the respective plurality ofCDD-based precoding matrices at least in part by determining, for each(or any) PRS of the plurality of PRSs, a cyclical delay parameter forthat PRS. The cyclical delay parameter may be specific to the PRS. In anembodiment, the device may determine the respective plurality ofCDD-based precoding matrices at least in part by adapting the CDD-basedprecoding matrix for each (or any) PRS using the determined cyclicaldelay parameter specific to that PRS.

In an embodiment, the second matrix may be adapted to provide phasecontinuity from the first precoded PRS by forcing a starting phase of acyclical phase shift of the second PRS to start from an ending phase ofa cyclical phase shift of the first PRS. In an embodiment, each PRS mayinclude a fraction, or a bundle, of resource blocks.

A MIMO system with N_(RB) scheduled resource blocks for transmission maybe considered where the N_(RB) scheduled resource blocks may or may notbe contiguous. Each N_(RB) scheduled resource block may define M_(RE)resource elements.

In an embodiment, the frequency selective phase-continuous precoding maybe constructed and/or defined as y=W₁W₂x, where W₁, W₂ may be first andsecond beamforming matrices, and x may be a vector of transmit symbols.The first beamforming matrix W₁ may be determined as a wideband precoderfor the entire scheduled channel. A choice of W₁=I, where I is anidentity matrix, transforms the system to a single precoder operation.

In an embodiment, the second beamforming matrix W₂ may be defined as aCDD beamforming operation that results in an artificial frequencyselective channel. For example, the second beamforming matrix W₂ may bedefined as:

W ₂ =W _(CDD) S   (1)

where W_(CDD) represents the CDD beamforming operation that results inan artificial frequency selective channel, and where matrix S may be aconfigurable precoding matrix. The matrix S, may be any of an identity,Hadamard, an LTE-based precoder, etc. Alternatively, the matrix S may bedynamically configured or cycled over a predefined set of potentialprecoders.

The second beamforming matrix W₂ and/or the CDD beamforming matrix,W_(CDD) may be defined per set of N_(RE) resource elements. A PRS may bedefined as a fraction, or a bundle, of resources blocks, such that thenumber of resources elements per PRS is N_(RE)≤M_(RE). The number ofPRSs in a scheduled transmission may be represented by N_(PRS).

In an OFDM-based system with an inverse fast Fourier transform (IFFT)size of N_(IFFT), N_(RE) resource elements per PRS and v antenna ports,a CDD-based beamforming matrix W₂ and a CDD beamforming matrix, W_(CDD),for the l_(th) PRS may be defined as a diagonal matrix, as follows:

$\begin{matrix}{W_{2{({l,i})}} = {\Theta_{l}\begin{bmatrix}1 & 0 & \ldots & 0 \\0 & e^{{- j}\frac{2\pi \kappa_{l}i}{N_{RE}}} & \ddots & \vdots \\\vdots & \ddots & \ddots & 0 \\0 & \ldots & 0 & e^{{- j}\frac{2\pi \kappa_{l}{i{({\upsilon - 1})}}}{N_{RE}}}\end{bmatrix}}_{\upsilon \times \upsilon}} & \left( {2a} \right) \\{W_{CD{D{({l,i})}}} = {\Theta_{l}\begin{bmatrix}\ddots & 0 & 0 \\0 & e^{{- j}\frac{2\pi \kappa_{l}{i{({\upsilon ­2})}}}{N_{RE}}} & 0 \\0 & 0 & e^{{- j}\frac{2\pi \kappa_{l}{i{({\upsilon ­1})}}}{N_{RE}}}\end{bmatrix}}_{\upsilon \times \upsilon}} & \left( {2b} \right)\end{matrix}$

where κ_(l)∈

⁺ is a cyclic delay parameter; i is subcarrier index within the l_(th)PRS, where 0≤i≤N_(RE)−1; and l represents the PRS index, where1≤l≤N_(PRS). The matrix Θ_(l) is a diagonal matrix that enforces aninitial phase offset. For the first PRS (l=1), if no phase offset isdesired, then the matrix Θ₁ may be set to identity (e.g., the matrixΘ₁=I). Each of the l PRSs may feature a different κ_(l) parameter, andeach RE may be precoded differently.

To assure phase continuity of the effective channel across the l PRSs,the matrix Θ_(l) (l>1) may be modified as follows:

$\begin{matrix}{\Theta_{l} = {W_{2{({{l - 1},{N_{RE} - 1}})}} = \begin{bmatrix}1 & 0 & \ldots & 0 \\0 & e^{{- j}\frac{2\pi {\kappa_{l - 1}{({N_{RE} - 1})}}}{N_{RE}}} & \ddots & \vdots \\\vdots & \ddots & \ddots & 0 \\0 & \ldots & 0 & e^{{- j}\frac{2\pi {\kappa_{l - 1}{({N_{RE} - 1})}}{({\upsilon - 1})}}{N_{RE}}}\end{bmatrix}_{\upsilon \times \upsilon}}} & \left( {3a} \right) \\{\Theta_{l} = {W_{CD{D{({{l - 1},{N_{RE} - 1}})}}} = {\Theta_{l - 1}\left\lbrack {\begin{matrix}\ddots & 0 \\0 & e^{­j\frac{2\pi {\kappa_{l­1}{({N_{RE}­1})}}{({\upsilon ­2})}}{N_{RE}}} \\0 & 0\end{matrix}\begin{matrix}0 \\0 \\e^{­j\frac{2\pi {\kappa_{l­1}{({N_{RE}­1})}}{({\upsilon ­1})}}{N_{RE}}}\end{matrix}} \right\rbrack}_{\upsilon \times \upsilon}}} & \left( {3b} \right)\end{matrix}$

where such matrix Θ_(l) (l>1) may represent a phase state of theprecoder of a last subcarrier of a previous one of the l PRSs. Inclusionof the matrixΘ_(l) may cause a starting phase of the cyclical phaseshift of the l_(th) PRS to start from a last CDD phase of the (l_(th)−1)PRS. A benefit of using the matrixΘ_(l) is that abrupt phase transitionsover the boundaries of the l PRSs may be mitigated. The representativephase-continuous precoding using CDD provided herein may also be usedfor non-contiguous resource blocks assuming the non-contiguous resourceblocks are in close proximity (e.g., one of the non-contiguous resourceblocks is in close proximity to another one of the non-contiguousresource blocks).

In an embodiment, a transmitter unit may select the cyclic delayparameter κ_(l) per PRS from a set of predefined values. The predefinedset may be fixed or configurable. The fixed set may be defined orderived based on a cell-based feature, such as system bandwidth ordeployment requirement, e.g., urban vs. suburban. The configurable setmay be defined or derived based on any of mobility status of a WTRU,multi-user MIMO (MU-MIMO) requirement; and MIMO channel characteristics(e.g., rank).

The cyclic delay parameter κ_(l) may be adaptively selected based on anestimated CSI per PRS. The estimated CSI may be based on any of a directmeasurement on reference signals, a reported value and channelreciprocity. By adaptive adjustment of the cyclic delay parameter κ_(l),the frequency selectivity of the effective channel per PRS may beadjusted across the antennas. The resulting adjustment across theantennas may be to optimize a MIMO performance metric, for example. Themetric optimization may include any of maximizing capacity, maximizingSNR/SINR/SNLR, etc.

FIG. 4 is a graph illustrating a capacity comparison of adaptive CDDprecoding with other precoding mechanisms. The comparison is based oncapacity estimates of a 4×4 MIMO system. As the benchmark, computedcapacities of a full SVD and LTE-based beamforming are shown. For thepresented evaluation, MMSE beamforming was used. In the case of adaptiveCDD, different values or resolution/step for cyclic delay parameterκ_(l) were used. As shown, the LTE-based precoding and adaptive CDDperform similarly. And as can be readily discerned, no notableimprovement is exhibited when high resolution feedback for cyclic delayparameter κ_(l) is used.

The cyclic delay parameter κ_(l) may be selected based on any of WTRUmobility and channel characteristics (e.g., for open loop MIMO).Alternatively, the cyclic delay parameter κ_(l) may be selected randomlyor cycled over a predefined set of values.

For UL MIMO, a WTRU may determine the cyclic delay parameter κ_(l) setfrom control signaling, such as any of RRC signaling and dynamic L1control signaling. Alternatively, a WTRU may autonomously determine thebest cyclic delay parameter κ_(l).

The WTRU may indicate to the network that it is using per-tone precoding(and/or indicate that it is using per-tone precoding and not widebandprecoding) by transmitting one bit of feedback. The WTRU may indicate tothe network the cyclic delay parameter κ_(l) set determined by the WTRUfrom a pre-specified set of cyclic delay parameters κ_(l) that can beused by the network for UL multi-user MIMO operation. This informationmay be transmitted on any of an UL feedback channel, an UL dataassociated control channel and UL data.

For open-loop MU-MIMO, each co-scheduled WTRU may use a different set ofparameters for CDD precoding. Alternatively, each co-scheduled WTRU mayuse the same set (or different non-orthogonal set) of parameters for CDDprecoding because there is no need to have orthogonal precoders acrossmultiple WTRUs transmitting on the same allocation. The network may havean option to indicate the set of CDD parameters to the co-scheduledWTRUs. The WTRU should (but need not) follow the information provided bythe network in determining its CDD parameters.

A procedure that smooths time-representations of precoding vectors so asto ensure the impact of precoder on the data symbols are continuous hasbeen proposed in [1]. The proposal in [1] appears to rely on asupposition that, if a precoding vector p_(i,j) has high frequencycomponents, then by pruning in its dual domain, i.e., time, it ispossible to make the precoding vector smooth in frequency. However, whenthe high-frequency components are pruned and converted back to time viaa DFT operation as proposed, the first and last elements of p_(i,j) maybe distorted (e.g., significantly distorted). The distortion is believedto be due to the fact that puncturing in frequency corresponds to acircular filtering operation; the result of which is that the first andlast elements of the vector q_(i,j) become similar to each other.However, in practice, the last and first elements of p_(i,j) may bedifferent, wherein the significance of such difference depends on thesize of p_(i,j). For example, if there are 48 subcarriers, i.e., M=48,the precoding vector may be in

^(48×1). After pruning 40 components in time-domain and converting it tofrequency domain causes the vector to have edge elements significantlydistorted, as shown in FIG. 5.

Representative Phase-Continuous Precoding with Non-Zero Edge SmoothingExample(s)

FIG. 6 is a flow chart illustrating a representative procedure 600 forperforming phase-continuous precoding with non-zero edge smoothing. Therepresentative procedure 600 may be implemented in a device such as abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). The representative procedure 600 may be implemented in a deviceother than a base station and a WTRU as well.

As shown in FIG. 6, the device may expand a first precoding vector bypadding the first precoding vector with zeros, e.g., at its head andtail (602). The device may perform an IDFT of the expanded precodingvector to convert the expanded precoding vector to a time domain signal(604). The device may prune the time domain signal (606). The device mayperform a discrete Fourier transform (DFT) of the pruned time domainsignal so as to form a second precoding vector (608). The secondprecoding vector may have the same dimensions as the first precodingvector.

In an embodiment, the device may expand the first precoding vector(602), at least in part, by any of (i) inputting zeros at head and/ortail inputs of the IDFT, and (ii) inputting the precoding vector toinputs of the IDFT between the head and tail inputs of the IDFT. In anembodiment, the device may prune the time domain signal (606), at leastin part, by setting one or more elements of the time domain signal tozero. Such elements of the time domain signal may include a group or aset of elements that correspond to high frequency components of the timedomain signal.

In an embodiment, the frequency selective phase-continuous precoding maybe constructed and/or defined as y=W₁W₂x, where W₁, W₂ are first andsecond beamforming matrices, and x is a vector of transmit symbols. Thefirst beamforming matrix W₁ may be determined as a wideband precoder forthe entire scheduled channel. A choice of W₁=I for the first beamformingmatrix, where I is an identity matrix transforms the system to a singleprecoder operation.

In an embodiment, the second beamforming matrix W₂ the may includeseveral precoding vectors. For example, the second beamforming matrix W₂may be chosen as diag{{tilde over (P)}₁, {tilde over (P)}₂, . . . ,{tilde over (P)}_(m), . . . , {tilde over (P)}_(M)}, where diag{⋅} is anoperator for block diagonalization and {tilde over (P)}_(m) is a derivedprecoding matrix for mth subcarrier or subblock. The derived precodingmatrix {tilde over (P)}_(m) may be based on a set of original precoders{P₁, P₂, . . . , P_(k), . . . , P_(K)}. The precoding vector p_(i,j) maybe a column vector, as [{P₁}_(i,j), {P₂}_(i,j), . . . , {P_(m)}_(i,j), .. . , {P_(M)}_(i,j)]^(T) where its mth element is populated with theelement located on ith row and jth column of the precoding matrix P_(m)for mth subcarrier or subblock. The precoding vector p_(i,j) may beexpanded to a vector {tilde over (p)}_(i,j)=[h_(i,j) ^(T) p_(i,j) ^(T)t_(i,j) ^(T)]^(%)∈

^(M+T×1), where h_(i,j)∈

^(T) ¹ ^(×a) and t_(i,j)∈

^(T) ² ^(×1) are functions of p_(i,j) and T₁+T₂=T. After the vectorp_(i,j) is expanded, a time-domain filtering operation on {tilde over(p)}_(i,j) may be applied by using the following operations:

1) perform a M+T IDFT,

2) prune the resultant time domain signal (e.g., set some of theelements to zero; for example a group of elements that correspond tohigher frequency components), and

3) perform a M+T DFT.

The size of a resulting vector after the time domain filtering operationmay be in

^(M+T×1). The first T₁ and the last T₂ elements of the resulting vectormay be punctured. A result of the forgoing operations is that distortedelements are removed. FIG. 7 illustrates an example flow of theforegoing operations.

Without loss of generality, h_(i,j)∈

^(T) ¹ ^(×1) and t_(i,j)∈

^(T) ² ^(×1) may be derived based on p_(i,j). For example,

-   -   {h_(i,j)}_(k)={p_(i,j)}₁, {t_(i,j)}_(m)={p_(i,j)}_(M), i.e., the        elements of h_(i,j) are identical and equal to the first element        of p_(i,j) and the elements of t_(i,j) are identical and equal        to the last element of p_(i,j)    -   {h_(i,j)}_(k)=2{p_(i,j)}₁−{p_(i,j)}₂,        [t_(i,j)]_(m)=2{p_(i,j)}_(M)−{p_(i,j)}_(M−1), i.e., the elements        of h_(i,j) are identical and derived based on the        differentiating first two consecutive samples, and the elements        of t_(i,j) are identical and derived based on the        differentiating last two consecutive samples

FIG. 8 includes two graphs illustrating a performance comparison ofphase-continuous precoding with non-zero edge smoothing and otherprecoding methods In FIG. 8, the performance of the phase-continuousprecoding with non-zero edge smoothing is compared with the method givenin [1] and the real and imaginary parts of {{tilde over (p)}_(i,j)}_(n)are plotted, where n is the subcarrier index. While the method in [1]causes significant distortion on the edge elements of {tilde over(p)}_(i,j), application of the phase-continuous precoding with non-zeroedge smoothing results in significantly less distortion on the edges.

Representative Phase-Continuous Precoding with Phase Transition RegionExample(s)

FIG. 9 is a flow chart illustrating a representative procedure 900 forperforming phase-continuous precoding with a phase transition region.The representative procedure 900 may be implemented in a device such asa base station (e.g., any of the base stations 114, eNode-Bs 160, gNBs180 and base stations 202) or a WTRU (e.g., any of the WTRUs 102 andWTRUs 204). The representative procedure 900 may be implemented in adevice other than a base station and a WTRU as well.

As shown in FIG. 9, the device may obtain first and second precodingmatrices (e.g., from one or more codebooks) (902). The device mayinterpolate the first and second precoding matrices to generate atransition region to provide phase continuity between the first andsecond precoding matrices (904). The transition region may have alength, and the length of the transition region may be fixed orconfigurable.

In an embodiment, phase-continuous precoding may be supported bycreating a codebook in which every precoder selection is pairwisecontinuous with the any other member of the codebook. As an alternative,matrix interpolation may be employed to facilitate a soft phasetransition across PRS boundaries. In this alternative, a fixed ordynamic phase-continuous transition region may be created based on, oralong with, an existing codebook. The transition region may use adefined matrix interpolation scheme in the codeword transitions. Asimple example of this is shown in the FIG. 10. As shown, rather than anabrupt transition between PMI1 and PMI2, a transition region is definedbetween the two resources that transitions PMI1 to PMI2 in aphase-continuous manner. The length of the interpolation region may befixed or configurable by higher layer signaling or L1 control.

FIG. 11 is a flow chart illustrating a representative procedure 1100 forperforming phase-continuous precoding with one or more phase transitionregions. The representative procedure 1100 may be implemented in a firstdevice, such as a base station (e.g., any of the base stations 114,eNode-Bs 160, gNBs 180 and base stations 202) or a WTRU (e.g., any ofthe WTRUs 102 and WTRUs 204). The representative procedure 1100 may beimplemented in a device other than a base station and a WTRU as well.

To carry out the representative procedure 1100, the first device maycommunicatively couple with a second device. The second device may be abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). In an embodiment, the second device may be a base station if thefirst device is a WTRU. Alternatively, the second device may be a WTRUif the first device is a base station.

As shown in FIG. 11, the first device may estimate a channel based on anon-precoded reference signal (RS) or a beam-formed RS (1102). Abeamformer may be used in addition to a precoder. The first device mayestimate a precoder (e.g., a “best” precoder) for each scheduled PRS ofa plurality of PRSs based on a MIMO performance criterion (1104). Thefirst device may estimate or otherwise determine a matrix interpolationmechanism (e.g., a “best” matrix interpolation mechanism) for atransition region between each (or at least two) PRSs of the pluralityof PRSs (1106). In an embodiment, the first device may determine thematrix interpolation mechanism estimation, at least in part, by any ofdefining the transition region(s) and determining matrix interpolationparameters based on one or more system parameters. The transitionregion(s) may be region(s) over which the matrix interpolation may beperformed. In an embodiment, the matrix interpolation parameters mayinclude any of envelope characteristics and sub-space or inter-columninterference parameters. The envelope characteristics may includeconstant modulus and/or cubic-metric requirements. The sub-space orinter-column interference parameters may include column-wiseorthogonality and/or semi-orthogonality parameters. In an embodiment,the transition region(s) may be fixed and/or standardized. In anembodiment, the transition region(s) may be dynamically estimated basedon channel or scheduled transmission bandwidth. For example, thetransition region(s) may be defined based on frequency selectivity ofthe channel and/or mobility.

As an option, (e.g., in a non-reciprocal system), the first device mayfeed back/forward toward the second device a representation of thechannel (1108). The representation of the channel may include a PMI forthe transmission in the control channel. Alternatively, therepresentation of the channel may include any of one or more PMIs andone or more SNRs.

As an option, the first device may feed back/forward toward the seconddevice one or more parameters for performing the matrix interpolation(1110).

The second device may construct a precoder (not shown). The seconddevice may transmit precoded information to the first device (notshown). The second device may inform the first device to indicate theuse of a phase-continuous precoder and/or other indication to activatechannel estimation smoothing (not shown).

The first device may transmit to the second device an indication of theuse of a phase-continuous precoder and/or other indication to activatechannel estimation smoothing (1112). The first device may feedback/forward toward the second device a second (in time) representationof the channel (1114). The second representation of the channel mayinclude any of one or more PMIS and one or more SNRs.

The second device may construct a phase-continuous precoder based atleast in part on the reconstructed quantized channel.

The second device may receive the second representation of the channel(not shown). The second device may reconstruct the quantized channelbased at least in part on the second representation (not shown). Thesecond device may construct a phase-continuous precoder based at leastin part on the reconstructed quantized channel. Alternatively, thesecond device may construct a phase-continuous precoder using any of themethods discussed herein.

Representative Phase-Continuous Precoding for Non-ContiguousTransmission Example(s)

In an embodiment, the first and second devices may treat allnon-contiguous groups independently and may allow channel estimationsmoothing only within contiguous PRSs. Alternatively, a parameterdefining a (e.g., maximum) inter-PRS distance for smoothing may bespecified. The parameter may be static, semi-static or dynamic.Resources that are greater than or do not fall within the specifiedinter-PRG distances may be processed independently.

In an embodiment, the second device may send to the first deviceinformation in the scheduling grant that identifies PRSs that may beprocessed together. Additional information such as weighting factors maybe sent between the first and second devices to assist with smoothingprocedures. Alternatively, the first device may semi-blindly testdifferent methods and compare with information sent by the seconddevice. This may be sent in a control channel. The control channel maybe the channel or channels in which the second device sends to the firstdevice a value of channel estimate at the boundary between PRSs forcomparison.

Representative Transmission Aspects and Procedures

Representative Phase-Continuous Precoding Capability Exchange andSignaling Example(s)

The gNB's capabilities may be signaled during initialization in theNR-PBCH and carried in the Master Information Block (MIB) or one of theSystem Information Blocks (SIBs). As this information might not benecessary for WTRU start-up, the information may be signaled in a lowerhierarchy (or secondary PBCH) in the case of a hierarchical ormulti-level NR-PBCH that transmits only essential information first

A WTRU's capability information may be provided to the network in acapability Information Element (IE), which may be signaled as a ChestPhase Continuity IE. The WTRU Capability IE may be an RRC message thatthe WTRU sends to network (in most cases during initial registrationprocess). The WTRU Capability IE may inform on all the details of itscapabilities. An example of WTRU Capability IE may be as follows:

-   -   ENUMERATED {phase_cont_channel, phase_cont_PMI, both, none,        spare},        where “phase_cont_channel” may indicate that the WTRU supports        phase-continuous precoder design based on the channel estimate,        “phase_cont_PMI” may indicate that the WTRU supports PMI based        phase-continuous precoders, “both” may indicate that the WTRU        supports both methods, “none” may indicate that the WTRU does        not support phase-continuous precoder design, and “spare” is        reserved for future usage.

Alternatively, the transmitter (the gNB and/or WTRU) may indicate if aspecific transmission is using phase-continuous precoders in the controlchannel (the NR-PDCCH for downlink transmission and the NR-PUCCH for ULtransmission).

Note that in a downlink multi-user transmission with receivers that area mix of phase-continuous precoder capable and not, the transmitter mayhave the following options:

-   -   1. Transmit using Phase-Continuous precoders only.    -   2. Transmit using non-Phase-Continuous precoders only.    -   3. Transmit using a mix of phase-continuous and        non-Phase-Continuous precoders.

In the uplink multi-user transmission scenario, each WTRU may transmitindependently and signal the gNB based on what is using. In one method,the gNB may restrict WTRU that are not capable of phase-continuousprecoding from joining the network.

The one-bit information regarding the per-tone precoding vs widebandprecoding can be transmitted on the UL control channel which carriesACK/NACK (e.g., PUCCH). Alternatively, the WTRU may indicate the one-bitinformation implicitly by embedding it into the DMRS. For example, theDMRS may be scrambled with a unique sequence for the per-tone precodingmode of operation and with a different scrambling sequence for widebandprecoding mode of operation.

As an alternative, the information regarding the per-tone DL precodingcan be implicitly indicated by the size of the PRG. The WTRU maydetermine activation of the per-tone precoding from the size of the DLscheduling grant. A DL scheduling grant with a specific size mayindicate per-tone precoding at gNB, for example.

In LTE, the sizes of the RBG and PRG are defined or determined asfunctions of the system bandwidth, as listed in Table 1 below.

TABLE 1 System BW (MHz) RBG Size PRG Size 1.4 1 1 3 2 2 5 2 2 10 3 3 154 2 20 4 2

In an embodiment, any contiguous scheduling selected from a pre-definedset of RBG sizes may indicate a PRG size as wide as any of the size ofthe scheduled RBs and other (e.g., predefined) value. A WTRU may detectper-tone precoding if it determines the size of contiguous schedulingRBs belongs to a pre-defined set. For example, in contrast to theentries in Table 1, any contiguous scheduling with RBG≥4 may indicate aPRG size as wide as the size of the scheduled RBs. And a WTRU may detectper-tone precoding if it determines a contiguous scheduling with RBG≥4.

In a localized or a distributed transmission, the PRG size may bedetermined from a configured RBG size. The RBG size may be signaled orotherwise provided on any of a dynamic and semi-static basis, and any ofL1, L2 and higher layer control signaling and/or channels.

For a given RBG size configuration, the PRG size may be determined fromthe size of one or more contiguous parts of the scheduled transmission.In an embodiment, with a localized or a distributed transmissionscheduled with contiguous parts of equal to or wider than x RBGs, thePRG size may be determined (e.g., set) as wide as the span of thecontiguous part of the transmission, or by another pre-defined rule.Table 2 shows an exemplary case where the PRG size is increased from 2to 4 RBs if the scheduled transmission has contiguous parts of widerthan x RBGs.

TABLE 2 System BW (MHz) RBG Size PRG Size 1.4 1 1 3 2 2 5 2 2 10 3 3 154 2 15 (If contiguous 4 4 parts are wider than x RBGs) 20 4 2 20 (Ifcontiguous 4 4 parts are wider than x RBGs)

In an embodiment, an information element or other portion (collectively“IE”) of a downlink control information (DCI) may be used to indicatewhether to use a predefined PRG size for an UL/DL transmission, forexample, a transmission of 1 or 2 PRBs. The DCI IE may be as small as asingle bit. The DCI IE may be (e.g., set to) one value to indicate to aWTRU to use of the predefined PRG size for the UL/DL transmission.Alternatively, the DCI IE may be (e.g., set to) another value to asignal to the WTRU to use an alternate rule to determine the PRG size.If the DCI IE is more than one bit, the DCI IE may be (e.g., set to) oneof multiple different values to signal to the WTRU to use a respectiveone of multiple alternative rules to determine the PRG size. Hereafter,DCI IE may be interchangeably used with DCI bit, DCI bit field, DCIfield, DCI code point, DCI state of a DCI field, and DCI state.

In an embodiment, absence of the DCI IE or DCI without such DCI IE, suchas a particular DCI format, may operate as a (e.g., implicit) signal tothe WTRU to use the alternate rule or to use one or more to the multiplealternative rules for determining the PRG size.

In an embodiment, the alternate/alternative rule for determining the PRGsize may be (e.g., be defined) based on the size of RBG, e.g.,PRG_size=k*RBG_size, where k may be a real non-zero number (e.g., apositive integer number). Alternatively, the alternate/alternative rulefor determining the PRG size may be based on and/or related to thebandwidth part and/or the scheduled bandwidth. In an embodiment, thealternate/alternative rule for determining the PRG size may be based on(and/or implemented using) Table 3 and where x may be a configured,predefined fixed value, or determined by assistance information (e.g.,UE assistance information) or feedback. Table 3 lists representativeexamples of the RBG and PRG sizes for various representative examples ofsystem bandwidth. In an embodiment, the RBG and PRG sizes (e.g., therepresentative examples thereof listed in Table 3) may be configured percell, per one or more sectors or other portion of a cell and/or perWTRU. The representative examples of the RBG and PRG sizes and systembandwidth listed in Table 3 are provided for the purpose of illustrationonly and is not limiting of the disclosed embodiments.

TABLE 3 System BW (MHz) RBG Size PRG Size   1.4 1 1  3 2 2  5 2 2 10 3 315 4 2 15 4 4 Exemplary conditions: If the scheduled bandwidth is widerthan x RBGs If contiguous parts are wider than x RBGs If the bandwidthparts are wider than x RBGs Etc. 20 4 2 20 4 4 Exemplary conditions: Ifthe scheduled bandwidth is wider than x RBGs If contiguous parts arewider than x RBGs If the bandwidth parts are wider than x RBGs Etc.

In an embodiment, multiple different PRG sizes may be considered for agiven system and/or scheduled bandwidth. The multiple different PRGsizes may include a small PRG size, a large PRG size and one or moremid-range PRG sizes, for example. The small PRG size may be consideredand/or used to enable and/or facilitate (e.g., very) narrow-bandfrequency selective precoding operation and/or precoder cycling. Thesmall PRG size may be small in that it is not as large as the mid-rangePRG sizes and/or is small as compared to the scheduled bandwidth (e.g.,a small fraction of the scheduled bandwidth). The large PRG size may beas wide as the RBG size or a (e.g., integer) multiple of the RBG size.Alternatively and/or additionally, the large PRG size may be asignificant fraction of a scheduled bandwidth part. The large PRG sizemay be considered and/or used to enable and/or facilitate an improvedchannel estimation at the receiver (WTRU). Each or any of the mid-rangePRG sizes may be based on (e.g., as a function of) the channel frequencyselectivity. Each or any of the mid-range PRG sizes may be directlylinked to, or otherwise based on, the configured RBG size. As anexample, a mid-range PRG size may be based on a function of theconfigured RBG size, such as PRG=RBG/2̂L, where L may be a fixed valueper RBG. The multiple different PRG sizes may include max PRG size. Themax PRG size may be a wideband bandwidth, a scheduled bandwidth or amaximum allowed bandwidth.

In an embodiment, a selection from among the different configurations(e.g., the above-noted configurations) may be realized by employing anIE (“selection IE”). The selection IE may be as small as a single bit.The selection IE may be signaled or otherwise provided on any of adynamic and semi-static basis, and any of L1, L2 and higher layercontrol signaling and/or channels, including, for example, DCI and/orRRC signaling.

In an embodiment, the selection IE may be a single bit of a DCI and maybe used to indicate a choice of one option over other options (e.g., oneof the small, large, mid-range PRG sizes over the other two PRG sizes).Additionally, selection distinction among the remaining options may bebased on any of explicit and implicit UE assistance.

In an embodiment, the selection IE may be a single bit and may be usedto indicate the choice of a first option (small PRG size) over the otheroptions (large and mid-range PRG sizes). The selection of a secondoption (large PRG size) over a third option (a mid-range PRG size) maybe based on any of explicit and implicit UE assistance. Alternatively,the selection of a second option (large PRG size) over a third option (amid-range PRG size) may be based on a one or more parameters of anothersystem configuration, e.g., CSI-RS, etc. Table 4 below lists an exampleset of values for different values of the selection IE. The selection IEmay be a single bit and may be used to indicate PRG size determinationmethod, wherein a first method may be based on an explicit determinationand a second method is based on an implicit determination. The explicitdetermination may use a PRG size which may be configured via a higherlayer signaling. The implicit determination may use two PRB sizes andone of the PRG size may be implicitly determined.

TABLE 4 Selection IE = 1 Selection IE = 0 Explicit determinationImplicit determination PRG PRG PRG RBG (Small) (Mid-size) (Large size) 21 1 2 4 1 2 4 8 1 4 8 16 1 4 16

There may not be much gain (e.g., in channel estimation accuracy) inusing very wide PRG sizes, (e.g., PRG sizes >8), and performancedegradation may result in channel with high frequency selectivity. Table5 below lists examples of two implicitly-determinable PRG size optionsin addition to an example explicitly-determinable small PRG size optionfor each RBG size in a system with an RBG size set of {2, 4, 8, 16}. Thetwo implicitly-determinable PRG size options may be mid and large PRGsize options. Alternatively, one of the two implicitly-determinable PRGsize options may be a max PRG size option. The max PRG size option maybe a wideband bandwidth, a scheduled bandwidth or a maximum allowedbandwidth.

TABLE 5 IE = 1 IE = 0 Explicit determination Implicit determination PRGPRG PRG RBG (Small) (Option 1) (Option 2) 2 1 1 2 4 1 2 4 8 1 4 8 16 1 48

Table 6 below lists examples of two implicitly-determinable PRG sizeoptions in addition to an example explicitly-determinable wideband (orscheduled bandwidth) PRG size option for each RBG size in a system withan RBG size set of {2, 4, 8, 16}. The two implicitly-determinable PRGsize options may be mid and large PRG size options. Alternatively, oneof the two implicitly-determinable PRG size options may be a max PRGsize option.

TABLE 6 IE = 0 IE = 1 Implicit determination Explicit determination PRGPRG RBG PRG (Option 1) (Option 2) 2 Wideband/Scheduled 1 2 Bandwidth 4Wideband/Scheduled 2 4 Bandwidth 8 Wideband/Scheduled 4 8 Bandwidth 16Wideband/Scheduled 4 8 Bandwidth

Table 7 below lists examples of two implicitly-determinable PRG sizeoptions in addition to an example explicitly-determinable wideband (orscheduled bandwidth) PRG size option for each RBG size in a system withan RBG size set of {2, 4, 8, 16}. The two implicitly-determinable PRGsize options may be small and large PRG size options. Alternatively, theone of the two implicitly-determinable PRG size options may be any twoof small, mid, large and max PRG size options.

TABLE 7 IE = 0 IE = 1 Implicit determination Explicit determination PRGPRG RBG PRG (Option 1) (Option 2) 2 Wideband/Scheduled 1 2 Bandwidth 4Wideband/Scheduled 1 4 Bandwidth 8 Wideband/Scheduled 1 8 Bandwidth 16Wideband/Scheduled 1 8 Bandwidth

In an embodiment, an implicit indication may be used to over-ride therole of selection IE to indicate use of a small PRG size (or any ofother option). An example of a condition triggering the implicitindication may be based on any of a configured transmission mode,specific use case, numerology, and parameters of another systemconfiguration, e.g., CSI-RS, etc. Additionally and/or alternatively, inabsence of the condition triggering the implicit indication, an IE(which may be as small as a single bit) may be used to indicate dynamicselection of a second option over other options. The IE, for example,may be used to indicate dynamic selection of frequency selective(mid-range PRG size) and wideband (large PRG size) precoding. Table 8below lists an example set of values for implicit and explicitdeterminations for different values of the IE.

TABLE 8 Implicit Explicit determination determination IE = 1 IE = 0 PRGPRG PRG RBG (Small) (Mid-size) (Large size) 2 1 1 2 4 1 2 4 8 1 4 8 16 14 16

In an embodiment, for every RBG size, a wireless transmit/receivingdevice (e.g., gNB and/or WTRU) may be configured with a default PRGsize. The IE may be configured and/or used to indicate a switch betweenthe small PRG size and the default PRG size (e.g., using a default valuedefined by the PRG). The default PRG size may be based on a (e.g.,fixed) relationship to, or function of, any of the RBG size, scheduledbandwidth, another system configuration parameter, and an arbitraryconfigured value. The small PRG size value may be a fixed size, forinstance. Alternatively, the small PRG size value may be configured(e.g., semi-statically) to take any of the {1, 2} PRB's. Table 9 belowlists example values for default and small PRG sizes based on exampleRBG and IE values.

TABLE 9 Explicit determination IE = 1 IE = 0 PRG PRG RBG (Small PRGsize) (Default PRG size) 2 1 2 4 1 4 8 1 8 16 1 8

In an embodiment, for every RBG size, a wireless transmit/receivingdevice (e.g., gNB and/or WTRU) may be configured with a set of valuesfor small, mid and large PRG sizes. Table 10 below lists example PRGsizes corresponding to each RBG in a system with an example RBG size setof {2, 4, 8, 16}.

TABLE 10 PRG PRG PRG RBG (Small) (Mid-size) (Large size) 2 1 1 2 4 1 2 48 1 4 8 16 1 4 8

In an embodiment, the mid-size PRG value may be considered as thedefault PRG size (e.g., responsive to a particular RBG sizeconfiguration). Alternatively, and/or additionally, the default valuemay be defined based on an implicit rule (e.g., scheduled transmission,system bandwidth, DMRS configuration, etc.). Alternatively, and/oradditionally, the default value may be defined based on a (e.g., direct)relationship to, and/or function of, the selected RBG size.Alternatively, and/or additionally, the default value may be arbitrarilyconfigured.

In an embodiment, an IE, e.g., a DCI field, may be turned on and off (orotherwise set) to assist PRG size selection. For example, if after RBGsize configuration the DCI bit field remains off, the PRG size remainsas the default value (e.g., the mid-size PRG). Alternatively, if the DCIbit field is turned on, a state b₀ may indicate a change in the PRG sizefrom the default value to a small PRG size, such as, e.g., 2 PRBs and/ora small PRG size that may be necessary for certain scenarios, such asMU-MIMO pairing. Alternatively, if the DCI bit field is on and the stateis set to b₁, the PRG size may be switched to a large PRG size (e.g., toenable better channel estimation). In an embodiment, a turned off DCIbit field may indicate (e.g., may always indicate) to maintain a currentPRG size.

In an embodiment, if the current PRG size is already set to the smallestPRG size, a turned-on DCI bit with state b₀ may indicate a switch (e.g.,a switch back) to the default value. Alternatively, if the current PRGsize is already set to the largest PRG size, a turned-on DCI bit withstate bi may indicate a switch (e.g., a switch back) to the defaultvalue. In an embodiment, both of the above-mentioned approaches may beused for switching back to the default value. Alternatively, only one ofthe above approaches is used for switching back to the default value,and the other state is reserved.

In an embodiment, a wireless transmit/receiving device (e.g., gNB and/orWTRU) may determine an implicitly determinable PRG size based on anyconfigured value and an appropriate rule (e.g., as noted supra). Theconfigured value may be, may be based on, may be related to and/or maybe a function of one or more parameters of various systemconfigurations, for example.

In an embodiment, the configured value may be based on, may be relatedto and/or may be a function of a size of an active bandwidth part. As anexample, the configured value may represent N contiguous PRBs of anactive bandwidth part. The active bandwidth part may be, for example, aconfigured RBG and/or a subband.

In an embodiment, the implicitly determinable PRG size may be based on afixed relation to the configured value. For example, where theconfigured value represents N contiguous PRBs of an active bandwidthpart, the implicitly determinable PRG size may be determined usingequation PRG=N×MPRBs, where M may be a fixed value, a configurable valueand/or determined based on the size of the active bandwidth part. In anembodiment, M may be any number (e.g., any integer) greater than orequal to 1 (i.e., M≥1) that results in precoding of M subbands with asame precoder. In an embodiment, M may be any number (e.g., any integer)that satisfies the following equation (1/N)<M<1 and that results in (i)partitioning of a subband and (ii) precoding of each part withpotentially a different precoder. In an embodiment, for a given N, thePRG size may be scaled based on a duration of a transmission. Theduration may depend on whether any of multi-slot (slot aggregation),slot and non-slot are used. For example, for a multi-slot transmission,the PRG size may be scaled down to provide higher transmissiondiversity.

In an embodiment, the configured value and/or the appropriate rule maybe, may be based on, may be related to and/or may be a function of alocation or range of a set of PRBs (“PRB location”) within a scheduledor other bandwidth. In an embodiment where (i) the scheduled or otherbandwidth may be partitioned into several parts (e.g., segments) and(ii) each part may be associated with a respective configured valuecorresponding to a (pre-)configured PRG size, the appropriate rule maybe to select the configured value ((pre-)configured PRG size)corresponding to a particular PRB location within such bandwidth. Thewireless transmit/receiving device (e.g., gNB and/or WTRU) may determinethe implicitly determinable PRG size using such rule, which may beimplemented using a lookup table, such as Table 11 below. Table 11 listsexample bandwidth parts of a scheduled or other bandwidth along withtheir respective configured values. The (pre-)configured PRG sizes ofdifferent parts may or may not be the same.

TABLE 11 RB Location Configured Value X₀ − X₁ RBs PRG size 1 X₁ + 1 − X₂RBs PRG size 2 . . . . . . X(_(Last−1)) + 1 − X_(Last) RBs PRG size K

In an embodiment, the multiple configured values for each part (e.g.,PRG size 1, PRG size 2, etc,) may be configured using any of L1, L2 andhigher layer control signaling and/or channels, including, for example,DCI and/or RRC signaling. In an embodiment, one of the multipleconfigured values may be considered as the default PRG size. A wirelesstransmit/receiving device (e.g., gNB and/or WTRU) may be configured toone of the remaining PRG sizes semi-statically or dynamically using anyof L1, L2 and higher layer control signaling and/or channels, including,for example, DCI and/or RRC signaling. Table 12 below lists twoconfigured values for each bandwidth part, namely, configured value 1and configured value 2. Each of the configured values 1 and 2 maycorrespond to a (pre-)configured PRG size. As listed in Table 12, theconfigured values 1 correspond to (e.g., preconfigured) default PRGsizes. The configured values 2 may be configured by RRC signaling ordynamically by content of a received IE.

TABLE 12 Configured Value 1 RB Location (Default PRG Size) ConfiguredValue 2 X₀ − X₁ RBs PRG size 1₁ PRG size 2₁ X₁ + 1 − X₂ RBs PRG size 1₂PRG size 2₂ . . . . . . . . . X(_(Last−1)) + 1 − X_(Last) RBs PRG size1_(K) PRG size 2_(K)

A wireless transmit/receiving device (e.g., gNB and/or WTRU) may beconfigured with different levels of density of DMRS in frequency andtime and/or a larger span in frequency than the actual resourceallocation. In an embodiment, the configured value and/or theappropriate rule may be, may be based on, may be related to and/or maybe a function of a DMRS configuration. For example, the appropriate rulemay be to select one of multiple configured values ((pre-)configured PRGsizes) based on a density of configured DMRS in a frequency domain. Awireless transmit/receiving device (e.g., gNB and/or WTRU) may determinethe implicitly determinable PRG size using such rule, which may beimplemented using a lookup table, such as Table 13 below. The density ofconfigured DMRS in the frequency domain may be based on the number ofDMRS subcarriers per symbol. Table 13 lists example DMRS densityconfigurations along with their respective configured values((pre-)configured PRG sizes).

TABLE 13 DMRS Density Configuration PRG Configuration 1a: 1 Symbol, Comb2 + 2 Cyclic Shift PRG size 1 Configuration 2a: 1 Symbol, 2-FD-OCC PRGsize 2 . . . . . .

In an embodiment, the appropriate rule may be to select one of multipleconfigured values ((pre-)configured PRG sizes) based on a density ofconfigured DMRS in a time domain. A wireless transmit/receiving device(e.g., gNB and/or WTRU) may determine the implicitly determinable PRGsize using such rule, which may be implemented using a lookup table,such as Table 14 below. The density of configured DMRS in the timedomain may be based on the number of DMRS symbols per slot. Table 14lists example DMRS density configurations along with their respectiveconfigured values ((pre-)configured PRG sizes).

TABLE 14 DMRS Density Configuration PRG Configuration 1a: 1 Symbol, Comb2 + 2 Cyclic Shift PRG size 1 Configuration 1b: 2 Symbols, 2 CyclicShift + 2-TD-OCC PRG size 2 . . . . . .

In an embodiment, a wireless transmit/receiving device (e.g., gNB and/orWTRU) may be configured with a DCI field that may be used for indicatingPRG size of a scheduled PDSCH. This DCI field may be as small as asingle bit. The DCI field may be any of the IEs provided herein supraand/or infra. The wireless transmit/receiving device may also beconfigured with one PRG candidate value or with multiple PRG candidatevalues. The PRG candidate value(s) may be configured using any of L1, L2and higher layer control signaling and/or channels, including, forexample, DCI and/or RRC signaling. The wireless transmit/receivingdevice may select one value from the one configured PRG candidate valueor the multiple configured PRG candidate values based on (e.g.,responsive to) the DCI field indicating (e.g., being set to) a firstvalue (e.g., a “1”). If two configured PRG candidate values are used,the one value may be implicitly determined. The wirelesstransmit/receiving device may determine which of the two (or multiple)PRG candidate value to use based on one or more of following:

One or more candidate values may be used and the candidate values mayinclude 2, 4, and scheduled bandwidth, wherein the candidate value maybe referred to as PRG size. As an example, three candidate values may beused such as PRG size 1 (PRG₁), PRG size 2 (PRG₂), and PRG size 2(PRG₃), where PRG size 1=2, PRG size 2=4, and PRG size 3=scheduledbandwidth.

One or more types of parameters (e.g., PRG parameters) may be used todetermine the PRG size between (among) two (or multiple) candidatevalues. The PRG parameter types may include any of a scheduledbandwidth, RBG size, a subband size for CSI reporting, a PDCCH REGbundling size, a bandwidth size, a bandwidth part size, a BWP size and aDMRS configuration. The DMRS configuration may include any of a DMRSpattern, a DMRS density within a PRB and slot, an orthogonalmultiplexing method (e.g., TD-OCC, FD-OCC), a number of orthogonal DMRSports and a number of symbols used for DMRS.

The PRG parameter type may be determined based on the configured two (ormultiple) PRG candidate values. For example, if a first set of PRGcandidate values {PRG₁, PRG₂} are configured for a DCI field indicating(e.g., set to) a first value (e.g., a “1”), a first PRG parameter type(e.g., DMRS configuration) may be used to determine the PRG size of thescheduled PDSCH. If a second set of PRG candidate values {PRG₁, PRG₃}are configured for the DCI bit field indicating (e.g., set to) a firstvalue (e.g., a “1”), a second PRG parameter type (e.g., RBG size) may beused to determine PRG size of the scheduled PDSCH between (among) two(or multiple) candidate values.

In an embodiment, if candidate values {PRG₁, PRG₂} are configured, then

PRG size=PRG₁, if DM-RS density satisfies (e.g., is higher than) athreshold; and/or

PRG size=PRG₂, if DM-RS density does not satisfy (e.g., is lower than)the threshold.

In an embodiment, if candidate values {PRG₁, PRG₂} are configured, then

PRG size=PRG₁, if DM-RS density satisfies (or alternately does notsatisfy) a first threshold; and/or

PRG size=PRG₂, if DM-RS density satisfies (or alternately does notsatisfy) a second threshold.

In an embodiment, if candidate values {PRG₁, PRG₃} are configured, then

PRG size=PRG₁, if scheduled bandwidth satisfies (e.g., is smaller than)a threshold (e.g., N_(RB)), and/or

PRG size=PRG₃, if scheduled bandwidth does not satisfy (e.g., is largerthan) the threshold (e.g., N_(RB)).

In an embodiment, if candidate values {PRG₁, PRG₃} are configured, then

PRG size=PRG₁, if scheduled bandwidth satisfies (or alternately does notsatisfy) a first threshold (e.g., N_(RB)), and/or

PRG size=PRG₃, if scheduled bandwidth satisfies (or alternately does notsatisfy) a second threshold (e.g., N_(RB)).

In an embodiment, if candidate values {PRG₂, PRG₃} are configured, then

PRG size=PRG₂, if RBG satisfies (e.g., is smaller than) a threshold(e.g., N_(RBG)); and/or

PRG size=PRG₃, if RBG does not satisfy (e.g., is larger than) thethreshold (e.g., N_(RBG))

In an embodiment, if candidate values {PRG₂, PRG₃} are configured, then

PRG size=PRG₂, if RBG satisfies (or alternately does not satisfy) afirst threshold (e.g., N_(RBG)); and/or

PRG size=PRG₃, if RBG satisfies (or alternately does not satisfy) asecond threshold (e.g., N_(RBG))

As an alternative, the wireless transmit/receiving device may select oneof the configured PRG candidate values based on (e.g., responsive to)the DCI field indicating (e.g., being set to) a second value (e.g., a“0”). The DCI field may be toggled between indicating the first valueand the second value so as may operate as an indication to switch fromone of the configured PRG candidate values to another (with or withoutcarrying out implicit selection differentiation).

An implicitly determinable PRG size may be determined in multiplestages. For example, if a DMRS density is higher (lower or otherwisesatisfies) than a predefined or configured threshold, a first candidatevalue may be used. Otherwise, the PRG may be determined based on anotherPRG parameter type (e.g., RBG size, scheduled bandwidth, bandwidth partsize, BWP size, etc.). If candidate values {PRG₁, PRG₂} are configuredand the DMRS density for a scheduled PDSCH satisfies (e.g., is higherthan) a threshold, then candidate value, PRG₁, may be used as the PRGsize. Otherwise (or alternatively), the PRG size may be determined basedon RBG size. For example, if the RBG size satisfies (e.g., is largerthan) a predefined threshold, then a first of the candidate values(e.g., PRG₁) may be used. If the RBG size does not satisfy (e.g., issmaller than) the predefined threshold, then a second of the candidatevalues may be used (e.g., PRG₂).

In an embodiment, if the scheduled bandwidth satisfies (e.g., is largerthan) a first threshold, then a larger (or largest) candidate valuewithin the configured candidate values may be used as the PRG size. Ifthe DMRS density satisfies (e.g., is higher than) a second threshold,then a smaller (or smallest) candidate value within the configuredcandidate values may be used as PRG size. If the scheduled bandwidthdoes not satisfy (e.g., is smaller than) the first threshold and theDMRS density does not satisfy (e.g., is lower than) the secondthreshold, then the PRG size may be determined based on RBG size.

The PRG size may be determined based on priorities of PRG parametertypes. One or more PRG parameter types may be used to determine PRG sizeand the PRG parameter types may have priorities to determine the PRGsize. For example, DMRS density may be considered as a highest priority.If a condition is met for the DMRS density, then the PRG size may bedetermined based on the DMRS density. If the condition is not met, thenthe second priority PRG parameter type (e.g., scheduled bandwidth) maybe used to determine the PRG size and so on. One or more following mayapply as priority of the PRG parameter types:

Example 1: DMRS density (or configuration)>scheduled bandwidth>RBGsize>BWP>subband size>PDCCH REG bundle size; and

Example 2: scheduled bandwidth>DM-RS density (or configuration)>RBGsize>subband size.

FIG. 12 is a flow chart illustrating a representative procedure 1200 foruse in connection with phase-continuous precoding. The representativeprocedure 1200 may be implemented in a first device, such as a basestation (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180 andbase stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs 204).The representative procedure 1200 may be implemented in a device otherthan a base station and a WTRU as well.

To carry out the representative procedure 1200, the first device maycommunicatively couple with a second device. The second device may be abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). In an embodiment, the second device may be a base station if thefirst device is a WTRU. Alternatively, the second device may be a WTRUif the first device is a base station.

As shown in FIG. 12, the first device may receive signaling indicatingtransmit precoding information (1202). The first device may determine aPRG size using any of the indicated transmit precoding information, arule for determining the PRG size and a configured PRG size (1204). Thefirst device may configure or reconfigure in accordance with thedetermined PRG size (1206). The first device may apply precoding inaccordance with the determined PRG size (1208).

In an embodiment, the signaling indicating transmit precodinginformation may be signaled or otherwise provided on any of a dynamicand semi-static basis, and any of L1, L2 and higher layer controlsignaling and/or channels. In an embodiment, the signaling indicatingtransmit precoding information may be as small as a single bit. In anembodiment, the signaling indicating transmit precoding information mayinclude information used for a purpose other than, or in addition to,transmit precoding, and wherein the transmit precoding information maybe inferable from the information used for a purpose other than, or inaddition to, transmit precoding. In an embodiment, the signalingindicating transmit precoding information may be or may include an IE.The IE may be any one or a combination of the IEs disclosed herein supraand/or infra. The IE may be as small as a single bit.

The rule may be provisioned into the first device using informationsignaled or otherwise provided on any of a dynamic and semi-staticbasis, and any of L1, L2 and higher layer control signaling and/orchannels. The rule may be any of the rules disclosed herein supra and/orinfra and/or include any of the information included in such rules. Forexample, as disclosed supra, the rule may include information fordetermining the PRG size from a configured RBG size. The RBG size may besignaled or otherwise provided on any of a dynamic and semi-staticbasis, and any of L1, L2 and higher layer control signaling and/orchannels. As another example, the rule may include information fordetermining the PRG size from a size of one or more contiguous parts ofthe scheduled transmission, as disclosed supra.

In an embodiment, the IE may be (e.g., set to) one value to indicate touse the predefined PRG size, and may be (e.g., set to) another value toa signal to use an alternate rule to determine the PRG size. If the IEis more than one bit, then IE may be (e.g., set to) one of multipledifferent values to signal to use a respective one of multiplealternative rules to determine the PRG size. In an embodiment, absenceof the IE or absence of the signaled information without the IE mayoperate as a (e.g., implicit) signal to use an alternate rule, or to useone or more of multiple alternative rules, for determining the PRG size.

In an embodiment, the first device may carry out the functions(1202)-(1216) on condition that it is configured for dynamic PRG sizeconfiguration. Alternatively, the first device might not carry out oneor more of the functions (1202)-(1216) on condition that it is notconfigured for dynamic PRG size configuration. A signaled IE for turningon or off the dynamic PRG size configuration may be used to configurethe first device.

FIG. 13 is a flow chart illustrating a representative procedure 1300 foruse in connection with phase-continuous precoding. The representativeprocedure 1300 may be implemented in a first device, such as a basestation (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180 andbase stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs 204).The representative procedure 1300 may be implemented in a device otherthan a base station and a WTRU as well.

To carry out the representative procedure 1300, the first device maycommunicatively couple with a second device. The second device may be abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). In an embodiment, the second device may be a base station if thefirst device is a WTRU. Alternatively, the second device may be a WTRUif the first device is a base station.

The representative procedure 1300 may be considered an embodiment of therepresentative procedure 1200 (FIG. 12). As shown in FIG. 13, the firstdevice may receive signaling from the second device (1302). The firstdevice may determine whether the signaling indicates that dynamic PRGsize configuration is turned on or off (1304). On condition that thesignaling indicates that dynamic PRG size configuration is turned on,the first device may determine which one of a plurality of configuredPRG size sets to select a candidate PRG size from based on a value of anIE included in the signaling (1306). The first device may determinewhether the determined PRG size set defines a single configured PRG size(1308). On condition that the determined PRG size set defines a singleconfigured PRG size, the first device may select the single configuredPRG size as the candidate PRG size (1310). The first device maydetermine whether the determined PRG size set defines a plurality ofconfigured PRG sizes (1312). On condition that the determined PRG sizeset defines a plurality of configured PRG sizes, the first device mayselect one of the plurality of configured PRG sizes as the candidate PRGsize based on a configured rule (1314). The first device may configureor reconfigure in accordance with the selected candidate PRG size(1316). If the first device determined that the signaling indicates thatthe dynamic PRG size configuration is turned on (1302), the first devicemay select any of a fixed and a default PRG size (1318).

The first device may receive signaling including an IE for configuringthe dynamic PRG size configuration (not shown), The first device mayconfigure for dynamic PRG size configuration in accordance with such IE(not shown).

In an embodiment, the IE may be as small as a single bit. The IE may bea PRG size indicator or like type IE and may be standardized.

In an embodiment, the configured rule may be any rule disclosed hereinsupra or infra. In an embodiment, the configured rule may explicitlyspecify which one of the plurality of configured PRG sizes to select. Inan embodiment, the configured rule may specify one or more criteria forimplicitly determining which one of the plurality of configured PRGsizes to select.

In an embodiment, the plurality of configured PRG sizes may includefirst and second PRG size options, and the configured rule may specifywhich one of the first and second PRG size options to select based atleast in part on a RBG size. Alternatively, the configured rule mayspecify which one of the first and second PRG size options to selectbased at least in part on a RBG size and any of explicit and implicitassistance information. In an embodiment, the configured rule mayspecify which one of the plurality of configured PRG sizes to selectbased at least in part on a RBG size and a prior configured PRG size. Inan embodiment, the RBG size may be signaled or otherwise provided on anyof a dynamic and semi-static basis, and any of L1, L2 and higher layercontrol signaling and/or channels.

In an embodiment, the configured rule may specify which one of theplurality of configured PRG sizes to select based at least in part on aparticular number of contiguous scheduled resource blocks. Theparticular number of contiguous scheduled resource blocks may be, forexample, a minimum number of contiguous scheduled resource blocks.

In an embodiment, the configured rule may specify which one of theplurality of configured PRG sizes to select based on any configuredvalue. In an embodiment, the configured value may be based on, relatedto and/or a function of a size of an active bandwidth part. The activebandwidth part may be any of a configured RBG and a subband.

In an embodiment, the configured rule may specify which one of theplurality of configured PRG sizes to select based on a fixed relation toa configured value. The configured value may represent N contiguousphysical PRBs of an active bandwidth part, and the fixed relationshipmay be defined as equation PRG=N×M PRBs, where M is a fixed value, aconfigurable value or determined based on the size of the activebandwidth part. M may be any number greater than or equal to 1 (i.e.,M≥1) that results in precoding of M subbands with a same precoder.Alternatively, M may be any number that satisfies equation (1/N)<M<1 andthat results in (i) partitioning of a subband and (ii) precoding of eachpart with potentially a different precoder. In an embodiment, for agiven N, the PRG size may be scaled based on a duration of atransmission.

In an embodiment, the configured value may be based on a PRB locationwithin a bandwidth. In an embodiment, the configured rule may specifywhich one of the plurality of configured PRG sizes to select based on aPRB location within a bandwidth. In an embodiment, the PRB location maybe associated with the one configured PRG size.

In an embodiment, the configured value may be based on a DMRSconfiguration. In an embodiment, the configured rule may specify whichone of the plurality of configured PRG sizes to select based on a DMRSconfiguration. For example, the configured rule may specify which one ofthe plurality of configured PRG sizes to select based on a density ofconfigured DMRS in any of a frequency domain and a time domain.

In an embodiment, the plurality of configured PRG sizes may includefirst and second PRG size options, and the configured rule may specifyselecting the first PRG size option based at least in part on apreference of the first PRG size option over and the second PRG sizeoption.

In an embodiment, the configured value may include a parameter of asystem configuration. In an embodiment, the configured value may includean arbitrary value.

In an embodiment, the plurality of configured PRG sizes may include afirst PRG size option, and the rule may specify selecting the first PRGsize option on condition that a configured state change indicateschanging from a current PRG size to the first PRG size option.

In an embodiment, a first wireless transmit/receiving device (e.g., gNBand/or WTRU) may determine the PRG size for frequency selectiveprecoding based on a received feedback. The first wirelesstransmit/receiving device may perform channel measurements based on a(e.g., configured) periodic or aperiodic reference signal transmission,e.g., CSI-RS, SRS and/or other type of reference signal. The firstwireless transmit/receiving device may estimate frequency selectivity ofthe channel based on the measurements. The estimate may be based on fullchannel response or on a sparse measurement. The first wirelesstransmit/receiving device may determine a degree of selectivity based onthe estimate of the frequency selectivity of the channel. The firstwireless transmit/receiving device may send an IE to a second wirelesstransmit/receiving device (e.g., WTRU and/or a gNB) to indicate (theestimate of) the frequency selectivity of the channel. The definition ofthe IE in relation to the estimate of the frequency selectivity of thechannel may be listed in a table and configured by the gNB and/or othernetwork element (e.g., semi-statically). The IE may be, for example, nbits representing 2^(n) different RBG sizes. The index in the table maycorrespond to different PRG size values per bandwidth part, service,numerology, etc.

The second wireless transmit/receiving device may detect the IE. Thesecond wireless transmit/receiving device may select the indicated PRGsize for precoding. The second wireless transmit/receiving device maytransmit a transmission precoded in accordance with the indicated PRGsize for precoding. The first wireless transmit/receiving device mayreceive, from the second wireless transmit/receiving device, thetransmission precoded in accordance with the indicated PRG size forprecoding.

For UL transmission, if gNB has determined the WTRU capability forper-tone precoding, it may trigger WTRU per-tone precoding by assigninga specific range of RBG sizes. As such, the WTRU may detect activationof per-tone UL precoding if it determines the size of the scheduled RBsis selected from a pre-defined set of RBG sizes.

The use (or not) of phase-continuous precoding may be signaled by thecontrol channel. The control channel may use its own separate referencesignals and precoders and the information may be decoded and used toestimate the channel for the data channel.

In the case of a common RS for the control channel and the data channel,the receiver may decode the control channel and on discovering that thedata channel is phase-continuously precoded, the receiver may implementchannel estimation smoothing to improve the performance of the datachannel decoding procedure.

In an embodiment, the receiver may blindly estimate if the precoders forthe data channel are phase-continuous. The receiver may first decode thedata assuming phase-continuous precoding, and on failure, then decodethe data assuming no phase-continuous precoding. Note that blindestimation may be used for the first few transmissions because afterdetermining that the precoders are phase-continuous, it may be assumedthat the precoders are likely stay that way.

Representative TPMI Mechanisms for Frequency Selective Precoding

In an uplink transmission with codebook-based frequency selectiveprecoding, one or more TPMI(s) to be used by a WTRU for an uplinktransmission and/or indications thereof may be provided by a gNB. TheTPMI indications may be signaled or otherwise provided (collectively“signaled”) on any of a dynamic and semi-static basis, and any of L1, L2and higher layer control signaling and/or channels, may be used.

In a codebook-based precoding, entries of the codebook may be addressedby (e.g., obtainable using) a TPMI. The size and/or the number of bitsused for each TPMI may correspond to the size of the codebook. As anexample, for each entry in the codebook to be uniquely addressable by aTPMI, the size and/or the number of bits used for each TPMI depends onthe number of entries in (size of) the codebook.

In an embodiment, a codebook may be defined for all or multiple WTRUs.Each WTRU may be directed to use (e.g., only use) a subset of thecodebook according to its transmission capability. The TPMI size may beadjusted according to WTRU transmission capability. A codebook subsetrestriction (CBSR) may be based on different operational requirements.For example, the CBSR may be realized for different purposes, such as:reducing inter-cell interference and/or intra-cell interference,assisting MU pairing, WTRU mobility, WTRU transmission capability, etc.For example, in NR, three forms of uplink transmission in form of WTRUcapabilities are currently considered, namely, full coherence,non-coherence and partial coherence.

Under full coherence, all ports corresponding to ports in an SRSresource can be transmitted coherently. Under non-coherence, all portscorresponding to ports in an SRS resource are not transmittedcoherently. Under partial coherence, ports pairs corresponding to portsin an SRS resource can be transmitted coherently. For each mode of WTRUcapability only a subset of the codebook may be required. As such, theTPMI size may be adjusted to match the multiplicity of the subset, andavoid using extra overhead for TPMI indication.

Table 15 below represents an example of a codebook for supporting 4Txrank 1 transmission.

TABLE 15 Codebook index Number of layers υ = 1 0-7$\frac{1}{2}\begin{bmatrix}1 \\1 \\1 \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\j \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\{- 1} \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\{- j} \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\1 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\j \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\{- 1} \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\{- j} \\{- 1}\end{bmatrix}$  8-15 $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\1 \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\j \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\{- 1} \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\{- j} \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\1 \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\j \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\{- 1} \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\{- j} \\1\end{bmatrix}$ 16-23 $\frac{1}{2}\begin{bmatrix}1 \\0 \\1 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\{- 1} \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\j \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\{- j} \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\{- j}\end{bmatrix}$ 24-27 $\frac{1}{2}\begin{bmatrix}1 \\0 \\0 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\0 \\1 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\0 \\0 \\1\end{bmatrix}$ — — — —

A TPMI having a size of (at least) 5 bits may be used to address allentries of the table. However, not all the entries of the codebook maybe needed for a given WTRU capability. For example, for a WTRU with onlynon-coherence transmission capability, a TPMI with a size of 2 bits maybe used to address any of the 24-27 entries. Table 16 below includes anexample of coverage of the codebook by employed TPMI for each case ofcoherence capability.

TABLE 16 Coherence capability Codewords Bits Fully coherent  0-27 5Partially coherent 16-27 4 Non-coherent 24-27 2

In an embodiment, if a WTRU is configured, the TPMI size may be solelydetermined by WTRU coherence transmission capability. Upon WTRUdeclaration of a certain coherence capability, both a gNB and the WTRUmay determine the TPMI size solely based on the declaration. As such,each coherence capability case may (e.g. directly) indicate the CBSR,such as shown in Table 17 below.

TABLE 17 Coherence capability Codewords Bits TPMI content Fully coherent 0-27 5 0-27 Partially coherent 16-27 4 0-15 Non-coherent 24-27 2 0-3 

In an embodiment, the indices of a TPMI may be reordered to match theTPMI content, such as set forth in Table 18 below. Unlike Table 16,Table 18 does not include entries 12-15

TABLE 18 Codebook index Number of layers υ = 1 24-31$\frac{1}{2}\begin{bmatrix}1 \\1 \\1 \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\j \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\{- 1} \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\{- j} \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\1 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\j \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\{- 1} \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\{- j} \\{- 1}\end{bmatrix}$ 16-23 $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\1 \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\{- 1} \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\{- j} \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\1 \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\j \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\{- 1} \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\{- j} \\1\end{bmatrix}$  4-11 $\frac{1}{2}\begin{bmatrix}1 \\0 \\1 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\{- 1} \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\j \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\{- j} \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\{- j}\end{bmatrix}$ 0-3 $\frac{1}{2}\begin{bmatrix}1 \\0 \\0 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\0 \\1 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\0 \\0 \\1\end{bmatrix}$ — — — —

TABLE 19 Coherence capability Codewords Bits TPMI content Fully coherent0-31 5 0-31 Partially coherent 0-11 4 0-11 Non-coherent 0-3  2 0-3 

In an embodiment, following a WTRU declaration of coherence transmissioncapability, a relevant CBSR may be indicated to the WTRU dynamically orsemi-statically. In case of a dynamic indication, the indicated CBSR mayexpire (or may be expired) after a certain number of transmissions, slotnumbers or upon expiry of a timer. Alternatively, the dynamicallyindicated CBSR may be indicated as part of an uplink SPS configuration(sps-ConfigUL), and may be applied upon SPS activation.

The codebook entries corresponding to each coherence transmissioncapability listed in Table 20 may be related to WTRU coherencetransmission capability as shown. In an embodiment, the TPMI size may bejointly determined by WTRU coherence transmission capability and gNBinstructions (e.g., based on the entries in Table 20).

TABLE 20 Codebook index Number of layers υ = 1 Configuration 1  0-15Full — — Coherent Configuration 2 16-23 Full Partial Coherence —Coherent Configuration 3 24-27 Full Partial Coherence Non CoherentCoherence

In an embodiment, upon declaration of WTRU coherence capability, a gNBmay configure the WTRU for a desired CBSR by using a bit-map thatmatches the multiplicity of subsets required for each WTRU coherencecapability. A 3-bit bit-map may be used for full coherence. A 2-bitbit-map may be used for partial coherence. And no bit map may be usedfor non-coherence. Other bit maps may be used as well.

In addition (or as an alternative) to WTRU coherence capability, thebit-map may reflect other considerations for defining the CBSR. Forexample, as shown in Table 21 below, the indices 0-15 may be split intwo different configurations, in case a gNB may prefer to only use asubset of 0-15 precoders. Similarly, the bit-map length may bedetermined according to the required support for WTRU transmissioncoherency.

TABLE 21 Codebook index Number of layers υ = 1 Configuration 1 0-7 Full— — Coherent Configuration 2  8-15 Full — — Coherent Configuration 316-23 Full Partial Coherence — Coherent Configuration 4 24-27 FullPartial Coherence Non Coherent Coherence

The WTRU configuration of the bit-map may be done through RRC signalingor dynamically. In case of a dynamic indication, the indicated CBSR mayexpire (may be expired) after a certain number of transmissions, slotnumbers or upon expiry of a timer. Alternatively, the dynamicallyindicated CBSR may be indicated as part of an uplink SPS configuration(sps-ConfigUL), and may be applied upon SPS activation.

FIG. 14 is a flow chart illustrating a representative procedure 1400 foruse in connection with (e.g., UL or DL) codebook based transmissionconfiguration. The representative procedure 1400 may be implemented in afirst device, such as a base station (e.g., any of the base stations114, eNode-Bs 160, gNBs 180 and base stations 202) or a WTRU (e.g., anyof the WTRUs 102 and WTRUs 204). The representative procedure 1400 maybe implemented in a device other than a base station and a WTRU as well.

To carry out the representative procedure 1400, the first device maycommunicatively couple with a second device. The second device may be abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). In an embodiment, the second device may be a base station if thefirst device is a WTRU. Alternatively, the second device may be a WTRUif the first device is a base station.

As shown in FIG. 14, the first device may transmit, to the seconddevice, a report reporting a transmission coherence capability of thefirst device (1402). The first device may receive, from the seconddevice, a CBSR commensurate with the reported transmission coherencecapability (1404). The first device may determine a TPMI size based onthe CBSR (1406). The first device may receive a TPMI, e.g., from thesecond device (1408). The first device may detect and/or decode the TPMIbased on the determined TPMI size (1410). The first device may determinecodebook subsets based on the received TPMI and the CBSR (not shown).

In an embodiment, the CBSR may be a higher layer parameter. In anembodiment, the reported transmission coherence capability may be any ofa fully coherent capability, a partially coherent capability and anon-coherent capability.

In an embodiment, the first device may reorder the indices of the TPMIbased on the CBSR. In an embodiment, the first device may receive higherlayer signaling including a bit map for configuring the WTRU with theCBSR, and may use the bit map to configure the itself with the CBSR.

FIG. 15 is a block diagram illustrating example frequency selectiveprecoding for transmission on multiple (a plurality of) subbandstransmission. As shown, the frequency selective uplink precoding may befor M (e.g., localized or distributed) subbands. Each subband of the Msubbands may define a bandwidth corresponding to frequency resources(collective subcarriers) of one or more RBs. The M subbands,collectively, may define a scheduled bandwidth for the WTRU.

M narrow-band precoders, {W(1), W(2), . . . , W(M)} corresponding to theM subbands, respectively, may be signaled implicitly or explicitly tothe WTRU for use in connection with a (e.g., likewise signaled) resourceallocation considered for the uplink transmission. The precoding W mayrepresent a single or a dual stage precoding mechanism. The subbandprecoding W may correspond to the second beamforming matrix W₂ if adual-stage codebook is supported.

In case of a configuration with a plurality of SRS ports to be used by aWTRU for an uplink transmission, SRIs may be provided by a gNB. The SRIsmay be used to associate TPMIs with the SRS ports. A single SRI may beused to associate a TPMI with one of the SRS ports or more than one (e,g., a group) of the SRS ports. In which case, the number of SRIsindicated by the gNB may be equal to, or less than, the number of TPMIsindicated by the gNB. In an embodiment, only some of the SRIs indicatedby the gNB are used to associate TPMIs with the SRS ports.

Representative Examples of Supplementary TPMI and SRI Mechanisms forFrequency Selective Precoding

For simplicity of exposition herein supra and infra, the disclosure andvarious disclosed embodiments are described, for the most part, inconnection with TPMIs and/or indications thereof. Those skilled in theart will recognize that some or all of the disclosure and variousdisclosed embodiments described in connection with TPMIs and/orindications thereof are (e.g., equally) applicable to SRIs.

Like a TPMI, a SRI may define a set of indices. The set of indicesdefined by a SRI may include a first index corresponding to (e.g.,identifying or indicative of) one or more SRS ports and a second indexcorresponding to (e.g., identifying or indicative of) a precoding matrixassociated with such SRS ports. Given that an SRI and a TPMI may have orone-to-one or a many-to-one relationship, an SRI may have a lengthdefined in accordance with a corresponding number of configured SRSports, and that number may be equal or less than the number of TPMIsindicated by the gNB. Those skilled in the art will recognize that someor all of the disclosure and various disclosed embodiments described inconnection with TPMIs and/or indications thereof may be modifiedaccordingly for SRIs.

Assuming single stage precoding, the signaled TPMIs may includenarrow-band and wide-band components. The wide-band component may bebased on a bandwidth equal or larger than the scheduled transmission.For example, in FIG. 15, {W(1), W(2), . . . , W(M)} may be narrow-bandprecoders, and W_(WB) may be a wide-band precoder (e.g., for any of thesystem bandwidth, available system bandwidth and an entire bandwidth aUE may support as a capability). The information about the wide-bandprecoder may be signaled at a same rate or a different rate as (e.g.,more/less frequently than) the narrow-band precoders. As an example ofthe different indication rate, the information regarding the narrow-bandprecoders may be signaled in each UL grant, and the informationregarding the wide-band precoder may be signaled less frequently, suchas in a one every few UL grants or a subset of a set of UL grants.Alternatively, the information regarding the wide-band precoders may besignaled in each UL grant, and the information regarding the narrow-bandprecoders may be signaled less frequently, such as in a one every few ULgrants or a subset of a set of UL grants. The terms “narrow-bandprecoder” and the terms “sub-band precoder” may be used hereininterchangeably.

A WTRU may decode the received narrow-band and wide-band indications attheir corresponding rates. In case of a change in resourcere-scheduling, a WTRU may use an available wide-band precoder for thenewly allocated resources until being informed of a change/update to W1.As an example and with reference to FIG. 16, an uplink resourceallocation for subframe (i+1) may be different from an uplink resourceallocation in subframe i. For transmission in subframe (i+1) where theuplink resource allocation includes resources at one or more allocatedsubbands not used for subframe i (“newly allocated subbands”), the WTRUmay use the W_(WB) for precoding of the resources at such newlyallocated subbands. For distributed resource allocations, the WTRU mayuse the W_(WB) for precoding of resources at newly allocated subbandswithin an earlier scheduled bandwidth.

A WTRU may receive a wide-band TPMI via a higher layer signaling (e.g.,MAC-CE or RRC) and narrow-band TPMIs in an uplink grant. The wide-bandTPMI may remain valid until it is updated or it may expire after aperiod of time (e.g., responsive to a timeout of a timer).Alternatively, the wide-band TPMI may be refreshed after a period oftime (e.g., to prevent its expiration).

A WTRU may receive a wide-band TPMI in an (e.g., each) uplink grantencoded with an RNTI. For example, one or more C-RNTIs may be allocatedto a WTRU and one of the C-RNTIs may be determined or selected toscramble CRC of an uplink grant DCI to indicate the wideband TPMI, andthe subband TPMIs may be indicated in the DCI.

In embodiment, the precoding information may be split into narrow-bandand mid-band W_(MB) precoder components. A mid-band component maycorrespond to a bandwidth that is wider than a bandwidth correspondingto a narrow-band component and narrower than the system bandwidth. Thespan of bandwidths of corresponding mid-band components may be as wideas the entire system bandwidth or less. The entire (e.g.,system/available) bandwidth may be divided in N (contiguous ornon-contiguous) parts/segments, and N mid-band precoders {W_(MB)(1),W_(MB)(2), . . . , W_(MB)(N)} may be signaled for precoding of theircorresponding N parts/segments. The information about the mid-bandprecoders and the narrow-band precoders may be signaled at a same or adifferent rate.

A WTRU may decode the received narrow-band and mid-band indications attheir corresponding rates. In case of a change in resourcere-scheduling, a WTRU may use the available mid-band precoder for thenewly allocated resources until being informed of a change/update to W1.As an example and with reference to FIG. 17, the entire (e.g., systemand/or available) bandwidth may be segmented into 4 parts and an uplinkresource allocation for subframe (i+1) may be different from an uplinkresource allocation in subframe i. For transmission in subframe (i+1)where the uplink resource allocation includes resources at newlyallocated subbands, the WTRU may employ a most relevant mid-bandprecoder, {W_(MB)(1), W_(MB)(2)}for precoding of resources at the newlyallocated subbands. For distributed resource allocations, the WTRU mayuse a W_(WB) (not shown) for precoding of resources at newly allocatedsubbands within an earlier scheduled bandwidth.

In an embodiment, a wideband TPMI with one or more best-M subband TPMIsmay be signaled in an associated uplink grant. For example, the best-Msubband TPMIs may be used for subband precoding for the selectedsubbands and the wideband TPMI may be used for the rest of subbandswithin the scheduled bandwidth.

Information (e.g., a bit field) indicating a wideband TPMI and best-MTPMIs with its associated best-M subband index may be provided in anuplink grant. For example, if K subbands (e.g., K>M) are located in ascheduled bandwidth, the wideband TPMI may be used for the K subbandsexcept for the those indicated as the best M subbands, and the subbandTPMI(s) may be used for the corresponding subbands indicated as best-Msubbands.

In an embodiment, the M value may be predetermined based on a systembandwidth. In an embodiment, the M value may be determined as a functionof the scheduled bandwidth or the number of subbands within a scheduledbandwidth. In an embodiment, the M value may be fixed. In an embodiment,the M value may be configured via a higher layer signaling. In anembodiment, the M value may be ‘0’ (for example, when DFT-s-OFDM is usedfor uplink waveform and/or there are no subband TPMIs in the uplinkgrant).

An indication of supplementary TPMI information might not be required invarious instances. In an embodiment, transmission of supplementary TPMIindications may be activated and/or de-activated, e.g., on an as neededbasis. In an embodiment, the transmission of supplementary TPMIindications may be initially deactivated and later activated.Alternatively, the transmission of supplementary TPMI indications may beinitially activated and later de-activated. The activation and/orde-activation occur responsive to explicit signaling and/or messaging.The activation and/or de-activation occur responsive to a timerexpiration, timeout or the like, implicit signaling and/or messaging,and/or other implicit method.

In an embodiment, a WTRU may be configured by higher layer signaling toactivate/de-activate the transmission of the supplementary TPMIinformation. In an embodiment, a WTRU may determine a presence of thesupplementary TPMI information dynamically by or based on the format ofa received PDCCH. If, for example, the indicated TPMI vector does notmatch the size of the scheduled transmission, then the presence of theTPMI information may be indicated as part of the DCI payload. In anembodiment, a WTRU may detect a presence of the supplementary TPMIinformation by examining an IE (which may be as small as a single bit)in the DCI. The IE may indicate the presence of the supplementary TPMIinformation in a separate payload transmitted in L1 (PDSCH) or L2 (MACCE).

FIG. 18 is a flow chart illustrating a representative procedure 1800 foruse in connection with phase-continuous precoding. The representativeprocedure 1800 may be implemented in a first device, such as a basestation (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180 andbase stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs 204).The representative procedure 1800 may be implemented in a device otherthan a base station and a WTRU as well.

To carry out the representative procedure 1800, the first device maycommunicatively couple with a second device. The second device may be abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). In an embodiment, the second device may be a base station if thefirst device is a WTRU. Alternatively, the second device may be a WTRUif the first device is a base station.

As shown in FIG. 18, the first device may receive signaling indicatingtransmit precoding information for a plurality of subbands of a firstbandwidth and for one or more other bandwidths (1802). The first devicemay determine, from the transmit precoding information, first and secondsets of precoders corresponding to the plurality of subbands of thefirst bandwidth and to the other bandwidths, respectfully (1804). Thefirst device may perform precoding of the first bandwidth subbands usingthe first precoders for transmission at a first transmission event(1806). The first device may perform precoding of newly assignedresources using at least some of the first and/or second precoders fortransmission at the second transmission event (1808). A benefit ofcarrying out representative procedure 1800 is that it reduces the numberof bits used for signaling transmit precoding information in that noadditional bits (or a reduced number of additional bits) are needed tosignal transmit precoding information for the second transmission event.

In an embodiment, the transmit precoding information may include firstand second TPMI indications. In an embodiment, the first TPMIindications may correspond to (e.g., respective) narrow-band precodercomponents. In an embodiment, the second TPMI indications may correspondto (e.g., respective) mid-band precoder components. In an embodiment,the second TPMI indications may correspond to (e.g., respective)wide-band precoder components. In an embodiment, the second TMPI maycorrespond to any of mid-band and wide-band precoder components. In anembodiment, the transmit precoding information may be as small as asingle bit. In an embodiment, the transmit precoding information may bean IE.

Referring now to FIG. 19, an example TPMI indication mechanism withsupplementary mid-band TPMI information is shown. The example TPMIindication mechanism of FIG. 18 may be considered an embodiment of therepresentative procedure 1800 (FIG. 18).

As shown in FIG. 19, the first device may receive signaling (e.g., aDCI) indicating a first grant for transmission at an ith slot along withnarrow band precoding TPMIs for the ith slot and supplementary mid-bandprecoding TPMIs (1902). The first device may use precoders correspondingto narrow band precoding TPMIs for the transmission at the ith slot(1904). The first device may receive signaling (e.g., a DCI) indicatinga second grant for transmission at the ith+n slot (1906). The firstdevice may use precoders corresponding to at least some of narrow bandprecoding TPMIs and/or mid-band precoding TPMIs for the transmission atthe ith+n slot (1908). Like representative procedure 1700, a benefit ofthe TPMI indication mechanism with supplementary mid-band TPMIinformation of FIG. 19 is that it reduces the number of bits used forsignaling transmit precoding information in that no additional bits (ora reduced number of additional bits) are needed to signal transmitprecoding information for the transmission at the ith+n slot. Someadditional bits may be used to signal transmit precoding information toprovide TPMIs for any portion the scheduled transmission bandwidth notpreviously indicated and/or to update previously specified TPMIs.

Representative Adaptive Resolution TPMI Mechanisms for FrequencySelective Precoding

For an uplink transmission, the TPMI indication may be signaled on anyof a dynamic and semi-static basis, and any of L1, L2 and higher layercontrol signaling and/or channels, may be used. The capacity of thecontrol channel for TPMI indication of M narrow-band precoders, {W(1),W(2), . . . , W(M)} may often be assumed fixed. The precoding W mayrepresent a single or a dual stage precoding mechanism. The subbandprecoding W may correspond to the second beamforming matrix W₂ if adual-stage codebook is supported.

Representative Adaptive Codebook Resolution Examples

The number of bits used for TPMI(s) indication in an uplink grant (DCI)may be fixed (e.g., notwithstanding that the number of scheduled RBsand/or the number of subbands corresponding to the scheduled RBs maychange from grant to grant). In such case, codebook subsampling may beused for one or more (e.g., each) subband. For example, the referencenumber of subbands may be defined, configured, or determined as a value,Nsub; if the number of subbands within the scheduled bandwidth is equalto or smaller than Nsub, all codewords in the codebook may be used forsubband TPMI(s). If the number of subbands within the scheduledbandwidth is larger than Nsub, codebook subsampling may be used forsubband TPMI(s), and the number of codewords in the codebook for subbandTPMI(s) may be limited.

In an embodiment, the codebook subsampling may be referred to as acodebook subset restriction with reduced TPMI indication. In anembodiment, the codebook subsampling may be predefined or predeterminedbased on the number of subbands in a scheduled bandwidth and/or theNsub. In one embodiment the Nsub may be predefined or fixed. In anembodiment, the Nsub may be configured via a higher layer signaling. Ifthe number of subbands is smaller than the Nsub, codebook oversamplingmay be used. The oversampling may be based on an oversampling factor ofthe codebook generation. For example, an oversampled DFT matrix may beused for the codebook and a reference oversampling factor (e.g., O=4)may be used when the number of subband is the same as Nsub and a largeroversampling factor (e.g., O=8) may be used when the number of subbandis smaller than Nsub.

Assuming a fixed capacity for the TPMI indication channel, in asolution, the size the employed codebook may be readjusted according toa change in size of the resource allocation. Therefore, the indicatedTPMI indices may refer to the corresponding members of a down-sampledmother codebook.

In an embodiment, a WTRU may decode the received control payload, suchas a DCI, and may determine therefrom a size of a resource allocationcorresponding to a received UL grant. From the decoded size of theresource allocation, the WTRU may further decode of the received TPMIinformation to determine the TPMIs per subband, determine a samplingrate of the mother codebook, and/or select a precoder per subband basedthe decoded TPMI per subband and the down-sampled codebook. In case of achange in resource re-scheduling, the WTRU may adopt the codebookdown-sampling process until being informed of a higher resolution for W1update.

Table 22 lists example parameters and corresponding values for carryingout codebook down-sampling. In accordance with Table 22, the number ofbits per TPMI may adjusted to support the 32 RB transmission with thesame DCI size that was used in subframe i, for 16 RB transmission.

TABLE 22 Subframe i Subframe (i + 1) Number of RBs scheduled 16 32 PRGsize 4 4 Number of bits per TPMI 4 2 DCI size 16 16 Codebook size 16 4

FIG. 20 is a flow chart illustrating a representative procedure 2000 foruse in connection with phase-continuous precoding. The representativeprocedure 2000 may be implemented in a first device, such as a basestation (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180 andbase stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs 204).The representative procedure 2000 may be implemented in a device otherthan a base station and a WTRU as well.

To carry out the representative procedure 2000, the first device maycommunicatively couple with a second device. The second device may be abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). In an embodiment, the second device may be a base station if thefirst device is a WTRU. Alternatively, the second device may be a WTRUif the first device is a base station.

As shown in FIG. 20, the first device may receive, e.g., from the seconddevice, signaling comprising a fixed number of bits for indicatingtransmit precoding information for (i) a number of subbands of a firstbandwidth assigned to the first device, and (ii) one or more secondbandwidths (2002). The first device may perform adaptive codebookresolution based on the indicated transmit precoding information (2004).Although not shown, the first device may (i) perform channelmeasurements based on a reference signal transmission; (ii) determine anestimate of frequency selectivity of the channel based on themeasurements; (iii) determine a degree of selectivity based on theestimate of frequency selectivity; and/or (iv) send, to the seconddevice, an IE indicating (the estimate of) the frequency selectivity ofthe channel.

In an embodiment, the first device may perform adaptive codebookresolution at least in part by carrying out codebook subsampling basedon the number of subbands. In an embodiment, the first device mayperform adaptive codebook resolution at least in part by carrying outcodebook subsampling based on the number of subbands satisfying athreshold. The threshold may be or may be based on a reference number ofsubbands. In an embodiment, the first device may perform adaptivecodebook resolution at least in part by carrying out codebookoversampling based on the number of subbands. In an embodiment, thefirst device may perform adaptive codebook resolution at least in partby carrying out codebook oversampling based on the number of subbandssatisfying a threshold, wherein the threshold is or is based on areference number of subbands.

Representative Adaptive PRG Sizing Examples

As noted above, the number of bits used for TPMI(s) indication in anuplink grant DCI may be fixed. It may be fixed notwithstanding that thenumber of RBs in the scheduled RBs may change from grant to grant. Insuch case, adaptive subband sizing may be used. Pursuant to adaptivesubband sizing, the number of subbands may be limited to a certainnumber (e.g., Nsub) and the number of RBs for a subband (e.g., precodingresource granularity; PRG) may be determined based on the number RBsscheduled. For example, the maximum number of subbands may be limited to4 (e.g., Nsub=4) if (i) the number PRBs allocated for an uplinktransmission is 32, (ii) the subband size may be determined as 8 PRBsand 4 TPMIs may be provided in the uplink grant.

In an embodiment, the maximum number of subbands may be predefined orfixed. In an embodiment, the maximum number of subbands may beconfigured via a higher layer signaling. In an embodiment, the maximumnumber of subbands may be determined based on the downlink DCI which ismatched with uplink grant DCI in terms of size. In an embodiment, themaximum number of subbands may be determined based on a system bandwidthor maximum supportable bandwidth by the WTRU.

Assuming a fixed capacity for the TPMI indication channel, in asolution, PRG size may be readjusted according to a change in size ofthe resource allocation. Therefore, the indicated TPMI indices may referto the corresponding new PRG size definition.

In an embodiment, a WTRU may decode the received control payload, suchas a DCI, to determine the size of a resource allocation correspondingto a received UL grant. From the decoded size of the resourceallocation, a WTRU may further decode the received TPMI information todetermine the TPMIs per subband and/or determine the PRG size. In caseof a change in resource re-scheduling, the WTRU may adopt the new PRGsize definition until being informed of a higher resolution for W1update.

Table 23 lists example parameters and corresponding values for carryingout adaptive PRG sizing. In accordance with Table 23, the DCI size isassumed fixed, and the size of the PRG is adjusted to support the 32 RBtransmission with the same DCI size that was used in subframe i, for 16RB transmission.

TABLE 23 Subframe i Subframe (i + 1) Number of RBs 16 32 PRG size 4 8Number of bits per TPMI 4 4 DCI size 16 16 Codebook size 16 16

FIG. 21 is a flow chart illustrating a representative procedure 2100 foruse in connection with phase-continuous precoding. The representativeprocedure 2100 may be implemented in a first device, such as a basestation (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180 andbase stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs 204).The representative procedure 2100 may be implemented in a device otherthan a base station and a WTRU as well.

To carry out the representative procedure 2100, the first device maycommunicatively couple with a second device. The second device may be abase station (e.g., any of the base stations 114, eNode-Bs 160, gNBs 180and base stations 202) or a WTRU (e.g., any of the WTRUs 102 and WTRUs204). In an embodiment, the second device may be a base station if thefirst device is a WTRU. Alternatively, the second device may be a WTRUif the first device is a base station.

As shown in FIG. 21, the first device may receive, e.g., from the seconddevice, signaling comprising a fixed number of bits for indicatingtransmit precoding information for (i) a number of subbands of a firstbandwidth assigned to the first device, and (ii) one or more secondbandwidths (2102). The first device may perform adaptive precodingresource granularity sizing based on the indicated transmit precodinginformation (2104). Although not shown, the first device may (i) performchannel measurements based on a reference signal transmission; (ii)determine an estimate of frequency selectivity of the channel based onthe measurements; (iii) determine a degree of selectivity based on theestimate of frequency selectivity; and/or (iv) send, to the seconddevice, an IE indicating (the estimate of) the frequency selectivity ofthe channel.

In an embodiment, the first device may perform adaptive precodingresource granularity sizing at least in part by determining and/orsetting precoding resource granularity based on allocated resources andthe fixed number of bits. In an embodiment, the first device maydetermine and/or sett the precoding resource granularity at least inpart by determining whether to adjust or maintain the number of subbandsbased on allocated resources and the fixed number of bits.

Representative PMI Re-Use Examples

For a given bandwidth part, a WTRU may be configured to have a fixednumber of TPMIs (N_(TPMI)) irrespective of the number of scheduled RBsfor transmission. The N_(TPMI) may be configured dynamically,semi-statically or may be determined based on a table in relation to thebandwidth part size. The overall number of bits used for TPMI(s) in anuplink grant DCI may be a fixed value. As such, upon configuration ofthe BWP, a WTRU may determine N_(TPMI) to assist TPMI DCI detection. Fora given bandwidth part, a WTRU may also be configured with a number ofsubbands for frequency selective precoding, (N_(Subband)).

In an embodiment, if the number of configured TPMIs is greater or equalto a number of configured subbands for frequency selective precoding,i.e., N_(TPMI)≥N_(Subband), one unique TPMI per subband may be assigned.FIG. 22 illustrates an example of such frequency selective precoding. Inaccordance with the example shown in FIG. 22, the number of configuredsubbands may match the number of TPMIs.

In an embodiment, if the number of configured TPMIs is less than thenumber of configured subbands for frequency selective precoding, i.e.,N_(TPMI)<N_(Subband), some TPMIs may be assigned to more than onesubband. In an embodiment, the TPMIs may be indicted only for a specificset of subbands. The specific set of subbands may be referred to asprimary subbands. A WTRU may use the received TPMIs intended for theprimary subbands for precoding of one or more of its adjacent subbands,where the adjacent subbands may be on one or both side of a primarysubbands. In an embodiment, the TPMI of a closest primary subband may beapplied. FIG. 23 illustrates an exemplary case of where the indicatedTPMIs of primary subband {1, 3, 5, 7} may also applied on theirimmediately next adjacent subbands {2, 4, 6, 8}.

The designation of the primary subbands may be based on a uniform andstructured pattern (e.g., as shown in FIG. 23) and/or based on anon-uniform pattern (e.g., as shown in FIG. 24).

A fair and balanced assignment of the primary subbands across thescheduled transmission may be supported. To do so, in an embodiment, thepattern of primary subbands may be cycled for each transmission event.FIG. 24 illustrates an exemplary case of non-uniform pattern withcycling. Alternatively and/or additionally, the pattern for designationof primary subbands may be randomly changed from one transmission eventto another. Alternatively and/or additionally, the pattern of theprimary subbands may be defined based on a time index, such as slotnumber, etc.

Although the representative examples regarding transmit precodinginformation provided herein are described in the context of the uplink,similar or complementary methods, procedures and technologies may beapplied in the context of the downlink in view of the foregoingdescription.

Incorporation by Reference

Incorporated herein by reference are:

Qualcomm Incorporated, “Discussion on phase continuity and PRBbundling”, 3GPP Tdoc R1-1612045, 3GPP TSG-RAN WG1 Meeting #87, Reno,USA, Nov. 14-18, 2016;

InterDigital Communications, “On Enhanced Frequency Selective Precodingfor MIMO Transmission”, 3GPP Tdoc R1-1700713, 3GPP TSG RAN WG1 AH NRMeeting, Spokane, USA, Jan. 16-20, 2017; and

PCT Patent Application No. PCT/US16/64551, filed Dec. 2, 2016.

Conclusion

Although features and elements are provided above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. The present disclosure is not to be limitedin terms of the particular embodiments described in this application,which are intended as illustrations of various aspects. Manymodifications and variations may be made without departing from itsspirit and scope, as will be apparent to those skilled in the art. Noelement, act, or instruction used in the description of the presentapplication should be construed as critical or essential to theinvention unless explicitly provided as such. Functionally equivalentmethods and apparatuses within the scope of the disclosure, in additionto those enumerated herein, will be apparent to those skilled in the artfrom the foregoing descriptions. Such modifications and variations areintended to fall within the scope of the appended claims. The presentdisclosure is to be limited only by the terms of the appended claims,along with the full scope of equivalents to which such claims areentitled. It is to be understood that this disclosure is not limited toparticular methods or systems.

It is also to be understood that the terminology used herein is for thepurpose of describing particular embodiments only, and is not intendedto be limiting. As used herein, the term “video” may mean any of asnapshot, single image and/or multiple images displayed over a timebasis. As another example, when referred to herein, the terms “userequipment” and its abbreviation “UE” may mean (i) a wireless transmitand/or receive unit (WTRU), such as described supra; (ii) any of anumber of embodiments of a WTRU, such as described supra; (iii) awireless-capable and/or wired-capable (e.g., tetherable) deviceconfigured with, inter alia, some or all structures and functionality ofa WTRU, such as described supra; (iii) a wireless-capable and/orwired-capable device configured with less than all structures andfunctionality of a WTRU, such as described supra; or (iv) the like.Details of an example WTRU, which may be representative of any WTRUrecited herein, are provided herein with respect to FIGS. 1A-1D.

In addition, the methods provided herein may be implemented in acomputer program, software, or firmware incorporated in acomputer-readable medium for execution by a computer or processor.Examples of computer-readable media include electronic signals(transmitted over wired or wireless connections) and computer-readablestorage media. Examples of computer-readable storage media include, butare not limited to, a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs). A processor in association with software may be used toimplement a radio frequency transceiver for use in a WTRU, UE, terminal,base station, RNC, or any host computer.

Variations of the method, apparatus and system provided above arepossible without departing from the scope of the invention. In view ofthe wide variety of embodiments that can be applied, it should beunderstood that the illustrated embodiments are examples only, andshould not be taken as limiting the scope of the following claims. Forinstance, the embodiments provided herein include handheld devices,which may include or be utilized with any appropriate voltage source,such as a battery and the like, providing any appropriate voltage.

Moreover, in the embodiments provided above, processing platforms,computing systems, controllers, and other devices containing processorsare noted. These devices may contain at least one Central ProcessingUnit (CPU”) and memory. In accordance with the practices of personsskilled in the art of computer programming, reference to acts andsymbolic representations of operations or instructions may be performedby the various CPUs and memories. Such acts and operations orinstructions may be referred to as being “executed,” “computer executed”or “CPU executed.”

One of ordinary skill in the art will appreciate that the acts andsymbolically represented operations or instructions include themanipulation of electrical signals by the CPU. An electrical systemrepresents data bits that can cause a resulting transformation orreduction of the electrical signals and the maintenance of data bits atmemory locations in a memory system to thereby reconfigure or otherwisealter the CPU's operation, as well as other processing of signals. Thememory locations where data bits are maintained are physical locationsthat have particular electrical, magnetic, optical, or organicproperties corresponding to or representative of the data bits. Itshould be understood that the embodiments are not limited to theabove-mentioned platforms or CPUs and that other platforms and CPUs maysupport the provided methods.

The data bits may also be maintained on a computer readable mediumincluding magnetic disks, optical disks, and any other volatile (e.g.,Random Access Memory (RAM”)) or non-volatile (e.g., Read-Only Memory(ROM”)) mass storage system readable by the CPU. The computer readablemedium may include cooperating or interconnected computer readablemedium, which exist exclusively on the processing system or aredistributed among multiple interconnected processing systems that may belocal or remote to the processing system. It should be understood thatthe embodiments are not limited to the above-mentioned memories and thatother platforms and memories may support the provided methods.

In an illustrative embodiment, any of the operations, processes, etc.described herein may be implemented as computer-readable instructionsstored on a computer-readable medium. The computer-readable instructionsmay be executed by a processor of a mobile unit, a network element,and/or any other computing device.

There is little distinction left between hardware and softwareimplementations of aspects of systems. The use of hardware or softwareis generally (but not always, in that in certain contexts the choicebetween hardware and software may become significant) a design choicerepresenting cost vs. efficiency tradeoffs. There may be variousvehicles by which processes and/or systems and/or other technologiesdescribed herein may be effected (e.g., hardware, software, and/orfirmware), and the preferred vehicle may vary with the context in whichthe processes and/or systems and/or other technologies are deployed. Forexample, if an implementer determines that speed and accuracy areparamount, the implementer may opt for a mainly hardware and/or firmwarevehicle. If flexibility is paramount, the implementer may opt for amainly software implementation. Alternatively, the implementer may optfor some combination of hardware, software, and/or firmware.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples may be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. In an embodiment,several portions of the subject matter described herein may beimplemented via Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs), digital signal processors (DSPs),and/or other integrated formats. However, those skilled in the art willrecognize that some aspects of the embodiments disclosed herein, inwhole or in part, may be equivalently implemented in integratedcircuits, as one or more computer programs running on one or morecomputers (e.g., as one or more programs running on one or more computersystems), as one or more programs running on one or more processors(e.g., as one or more programs running on one or more microprocessors),as firmware, or as virtually any combination thereof, and that designingthe circuitry and/or writing the code for the software and or firmwarewould be well within the skill of one of skill in the art in light ofthis disclosure. In addition, those skilled in the art will appreciatethat the mechanisms of the subject matter described herein may bedistributed as a program product in a variety of forms, and that anillustrative embodiment of the subject matter described herein appliesregardless of the particular type of signal bearing medium used toactually carry out the distribution. Examples of a signal bearing mediuminclude, but are not limited to, the following: a recordable type mediumsuch as a floppy disk, a hard disk drive, a CD, a DVD, a digital tape, acomputer memory, etc., and a transmission type medium such as a digitaland/or an analogue communication medium (e.g., a fiber optic cable, awaveguide, a wired communications link, a wireless communication link,etc.).

Those skilled in the art will recognize that it is common within the artto describe devices and/or processes in the fashion set forth herein,and thereafter use engineering practices to integrate such describeddevices and/or processes into data processing systems. That is, at leasta portion of the devices and/or processes described herein may beintegrated into a data processing system via a reasonable amount ofexperimentation. Those having skill in the art will recognize that atypical data processing system may generally include one or more of asystem unit housing, a video display device, a memory such as volatileand non-volatile memory, processors such as microprocessors and digitalsignal processors, computational entities such as operating systems,drivers, graphical user interfaces, and applications programs, one ormore interaction devices, such as a touch pad or screen, and/or controlsystems including feedback loops and control motors (e.g., feedback forsensing position and/or velocity, control motors for moving and/oradjusting components and/or quantities). A typical data processingsystem may be implemented utilizing any suitable commercially availablecomponents, such as those typically found in datacomputing/communication and/or network computing/communication systems.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely examples, and that in fact many other architectures may beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality may beachieved. Hence, any two components herein combined to achieve aparticular functionality may be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated may also be viewed as being “operably connected”, or“operably coupled”, to each other to achieve the desired functionality,and any two components capable of being so associated may also be viewedas being “operably couplable” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents and/or wirelessly interactable and/or wirelessly interactingcomponents and/or logically interacting and/or logically interactablecomponents.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, where only oneitem is intended, the term “single” or similar language may be used. Asan aid to understanding, the following appended claims and/or thedescriptions herein may contain usage of the introductory phrases “atleast one” and “one or more” to introduce claim recitations. However,the use of such phrases should not be construed to imply that theintroduction of a claim recitation by the indefinite articles “a” or“an” limits any particular claim containing such introduced claimrecitation to embodiments containing only one such recitation, even whenthe same claim includes the introductory phrases “one or more” or “atleast one” and indefinite articles such as “a” or “an” (e.g., “a” and/or“an” should be interpreted to mean “at least one” or “one or more”). Thesame holds true for the use of definite articles used to introduce claimrecitations. In addition, even if a specific number of an introducedclaim recitation is explicitly recited, those skilled in the art willrecognize that such recitation should be interpreted to mean at leastthe recited number (e.g., the bare recitation of “two recitations,”without other modifiers, means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

Further, the terms “any of” followed by a listing of a plurality ofitems and/or a plurality of categories of items, as used herein, areintended to include “any of,” “any combination of,” “any multiple of,”and/or “any combination of multiples of” the items and/or the categoriesof items, individually or in conjunction with other items and/or othercategories of items. Moreover, as used herein, the term “set” isintended to include any number of items, including zero. Additionally,as used herein, the term “number” is intended to include any number,including zero.

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein maybe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” “greater than,” “less than,” and the likeincludes the number recited and refers to ranges which can besubsequently broken down into subranges as discussed above. Finally, aswill be understood by one skilled in the art, a range includes eachindividual member. Thus, for example, a group having 1-3 cells refers togroups having 1, 2, or 3 cells. Similarly, a group having 1-5 cellsrefers to groups having 1, 2, 3, 4, or 5 cells, and so forth.

Moreover, the claims should not be read as limited to the provided orderor elements unless stated to that effect. In addition, use of the terms“means for” in any claim is intended to invoke 35 U.S.C. § 112, ¶ 6 ormeans-plus-function claim format, and any claim without the terms “meansfor” is not so intended.

1. A method implemented in a wireless transmit/receive unit (WTRU) inconnection with carrying out dynamic precoding resource block group(PRG) configuration, the method comprising: receiving, from a basestation, downlink control information (DCI) including a single bitinformation element (IE) to use for determining a PRG size of a physicaldownlink shared channel (PDSCH); determining which one of a plurality ofconfigured PRG size sets to select a candidate PRG size from based on avalue of the single bit IE; on condition that the determined PRG sizeset defines a single configured PRG size, selecting the singleconfigured PRG size as the candidate PRG size; on condition that thedetermined PRG size set defines a plurality of configured PRG sizes,selecting one of the plurality of configured PRG sizes as the candidatePRG size based on a configured rule; and configuring or reconfiguringthe WTRU in accordance with the selected candidate PRG size.
 2. Themethod of claim 1, further comprising: receiving radio resource control(RRC) signaling including a single PRG size or a plurality of PRG sizesfor each of the plurality of PRG size sets; and configuring theplurality of PRG size sets in accordance with the RRC signaling.
 3. Themethod of claim 1, further comprising: selecting a default PRG size oncondition that the WTRU is not configured for dynamic PRG sizeconfiguration; and configuring or reconfiguring the WTRU in accordancewith the default PRG size.
 4. The method of claim 1, wherein theconfigured rule specifies which one of the plurality of configured PRGsizes to select based on bandwidth part size and scheduled bandwidth. 5.The method of claim 1, wherein the configured rule: (i) explicitlyspecifies which one of the plurality of configured PRG sizes to select;(ii) specifies one or more criteria for implicitly determining which oneof the plurality of configured PRG sizes to select; (iii) specifieswhich one of the plurality of configured PRG sizes to select based atleast in part on a particular number of contiguous scheduled resourceblocks; (iv) specifies selecting a first PRG size options of theplurality of configured PRG sizes over a second PRG size options of theplurality of configured PRG sizes based at least in part on a preferenceof the first PRG size option over the second PRG size option; (viii)specifies selecting the first PRG size option on condition that a statechange indicates changing from a current PRG size to the first PRG sizeoption; or (ix) specifies selecting the second PRG size option oncondition that a state change indicates changing from a current PRG sizeto the second PRG size option.
 6. The method of claim 1, wherein theplurality of configured PRG sizes comprises first and second PRG sizeoptions, and wherein the configured rule specifies which one of thefirst and second PRG size options to select based at least in part on aresource block group (RBG) size.
 7. The method of claim 1, wherein theplurality of configured PRG sizes comprises first and second PRG sizeoptions, and wherein the configured rule specifies which one of thefirst and second PRG size options to select based at least in part on aresource block group (RBG) size and any of explicit and implicitassistance information.
 8. The method of claim 1, wherein the configuredrule specifies which one of the plurality of configured PRG sizes toselect based at least in part on a resource block group (RBG) size and aprior configured PRG size.
 9. The method of claim 6, wherein the RBGsize may be signaled or otherwise provided on any of a dynamic andsemi-static basis, and on any of L1, L2 and higher layer controlsignaling and/or channels.
 10. The method claim 1, wherein theconfigured rule specifies which one of the plurality of configured PRGsizes to select based on any configured value.
 11. The method of claim10, wherein the configured value comprises any of a parameter of asystem configuration and an arbitrary value, and wherein the configuredvalue is based on, related to or a function of any of a size of anactive bandwidth part and a location or range of a set of physicalresource blocks (PRBs) within a bandwidth.
 12. The method of claim 11,wherein the active bandwidth part is any of a configured RBG and asubband.
 13. The method of claim 1, wherein the configured rulespecifies which one of the plurality of configured PRG sizes to selectbased on a fixed relation to a configured value.
 14. The method of claim13, wherein the configured value represents N contiguous physicalresource blocks (PRBs) of an active bandwidth part, and the fixedrelationship is defined as equation PRG=N×M PRBs, where M is a fixedvalue, a configurable value or determined based on the size of theactive bandwidth part.
 15. The method of claim 14, wherein M is anynumber greater than or equal to 1 (i.e., M≥1) that results in precodingof M subbands with a same precoder.
 16. A wireless transmit/receive unit(WTRU) comprising circuitry, including a receiver and processor,configured to: receive, from a base station, downlink controlinformation (DCI) including a single bit information element to use fordetermining a PRG size of a physical downlink shared channel (PDSCH); oncondition that the single bit information element is a first value,configure or reconfigure the WTRU to use a first configured candidatePRG size as the PRG size of the PDSCH; and on condition that the singlebit information element is a second value: determine which one of secondand third configured candidate PRG sizes to select based on a configuredrule; and configure or reconfigure the WTRU to use the selected secondor third configured candidate PRG size as the PRG size of the PDSCH. 17.The WTRU of claim 16, wherein the circuitry is configured to: receiveradio resource control (RRC) signaling including a single PRG size or aplurality of PRG sizes for each of the plurality of configured PRG sizesets; and configure the plurality of configured PRG size sets inaccordance with the RRC signaling.
 18. The WTRU of claim 16, wherein thesecond and third configured candidate PRG sizes are two of threestandardized PRG sizes, and wherein one of the two of three standardizedPRG sizes is wideband.
 19. The WTRU of claim 16, wherein the circuitryis configured to: select a default PRG size on condition that the WTRUis not configured for dynamic PRG size configuration; and configure orreconfigure the WTRU to use the default PRG size as the PRG size of thePDSCH.
 20. The WTRU of claim 16, wherein the configured rule specifieswhich one of the second and third configured candidate PRG sizes toselect based on bandwidth part size and scheduled bandwidth.
 21. TheWTRU of claim 16, wherein the configured rule specifies: (i) explicitlyspecifies one of the second and third configured candidate PRG sizes toselect; (ii) specifies one or more criteria for implicitly determiningwhich one of the second and third configured candidate PRG sizes toselect; (iii) specifies which one of second and third configuredcandidate PRG sizes to select based at least in part on a resource blockgroup (RBG) size; (iv) specifies which one of second and thirdconfigured candidate PRG sizes to select based at least in part on aresource block group (RBG) size and any of explicit and implicitassistance information; (v) specifies which one of second and thirdconfigured candidate PRG sizes to select based at least in part on aresource block group (RBG) size and a prior configured PRG size; (vi)specifies which one of the second and third configured candidate PRGsizes to select based at least in part on a particular number ofcontiguous scheduled resource blocks; (vii) specifies selecting thesecond configured candidate PRG size based at least in part on apreference of the second configured candidate PRG size over the thirdconfigured candidate PRG size; (viii) specifies selecting the secondconfigured candidate PRG size on condition that a state change indicateschanging from a current PRG size to the second configured candidate PRGsize; or (ix) specifies selecting the third configured candidate PRGsize on condition that a state change indicates changing from a currentPRG size to the third configured candidate PRG size.
 22. The WTRU ofclaim 16, wherein the configured rule specifies which one of second andthird configured candidate PRG sizes to select based on any configuredvalue.
 23. The WTRU of claim 22, wherein the configured value comprisesany of a parameter of a system configuration and an arbitrary value, andwherein the configured value is based on, related to or a function ofany of a size of an active bandwidth part and a location or range of aset of physical resource blocks (PRBs) within a bandwidth.
 24. The WTRUof claim 23, wherein the active bandwidth part is any of a configuredresource block group (RBG) and a subband.
 25. The WTRU of claim 16,wherein the configured rule specifies which one of second and thirdconfigured candidate PRG sizes to select based on a fixed relation to aconfigured value.
 26. The WTRU of claim 25, wherein the configured valuerepresents N contiguous physical resource blocks (PRBs) of an activebandwidth part, and the fixed relationship is defined as equationPRG=N×M PRBs, where M is a fixed value, a configurable value ordetermined based on the size of the active bandwidth part.
 27. The WTRUof claim 26, wherein M is any number greater than or equal to 1 (i.e.,M≥1) that results in precoding of M subbands with a same precoder.